reid@decwrl.UUCP (Brian Reid) (11/01/86)
USENET READERSHIP SUMMARY REPORT for Oct 86
This is a monthly posting from the Network Measurement Project at the DEC
Western Research Laboratory in Palo Alto, California.
This survey is based on a sample of data taken from various USENET sites.
At the end of this message there is a short explanation of the measurement
techniques and the meaning of the various statistics.
The complete set of readership data (of which this is a summary) is posted
in mod.newslists
--------------------------------------------------------------------------
New this month: a version of arbitron that copes properly with all of the
new newsgroups, and also a new column of information in the report. We now
report the "propagation" of a newsgroup, which is how many sites get that
group at all.
--------------------------------------------------------------------------
Brian Reid
OVERALL SUMMARY:
This Estimated
Sample for entire net
Sites: 393 4800
Fraction reporting: 8.19% 100%
Users with accounts: 53873 658000
Netreaders: 12377 151000
Average readers per site: 31
Percent of users who are netreaders: 22.97%
Average traffic per day (megabytes): 1.596
Average traffic per day (messages): 663
Traffic measurement interval: last 21 days
Readership measurement interval: last 75 days
TOP 40 NEWSGROUPS IN ORDER BY POPULARITY
+-- Estimated total number of people who read the group, worldwide.
| +-- Actual number of readers in sampled population
| | +-- Propagation: how many sites receive this group at all
| | | +-- Recent traffic (messages per month)
| | | | +-- Recent traffic (kilobytes per month)
| | | | | +-- Participation ratio
| | | | | | +-- Cost ratio: $US/month/reader
| | | | | | | +-- Share: % of newsreader
| | | | | | | | who read this group.
V V V V V V V V
1 28000 2540 74% 17 41.3 0 0.01 20.5% net.general
2 25000 2307 64% 505 744.4 20 0.12 18.6% net.jokes
3 25000 2303 74% 114 1218.5 4 0.19 18.6% net.sources
4 24000 2186 58% 2 6.1 0 0.00 17.7% mod.announce
5 20000 1783 66% 24 807.7 1 0.16 14.4% mod.sources
6 19000 1762 67% 64 201.2 3 0.04 14.2% net.jobs
7 16000 1469 72% 245 380.1 15 0.09 11.9% net.unix
8 15000 1407 65% 108 291.9 7 0.08 11.4% net.ai
9 15000 1361 73% 357 671.1 23 0.18 11.0% net.unix-wizards
10 14000 1303 62% 2 2.0 0 0.00 10.5% net.sources.games
11 14000 1268 63% 341 523.1 24 0.15 10.2% net.micro.mac
12 14000 1260 69% 622 2342.3 44 0.66 10.2% net.micro.pc
13 14000 1253 67% 132 228.3 9 0.06 10.1% net.micro
14 14000 1249 66% 65 101.2 4 0.03 10.1% net.graphics
15 14000 1232 63% 125 362.5 8 0.10 10.0% net.arch
16 14000 1230 72% 30 64.2 2 0.02 9.9% net.sources.bugs
17 13000 1224 64% 44 44.2 3 0.01 9.9% net.wanted
18 13000 1154 71% 47 64.6 3 0.02 9.3% net.sources.d
19 13000 1152 65% 5 26.8 0 0.01 9.3% mod.conferences
20 13000 1148 66% 198 322.9 15 0.10 9.3% net.lang.c
21 13000 1139 61% 364 615.2 28 0.19 9.2% net.movies
22 12000 1066 72% 64 175.5 5 0.06 8.6% net.news.group
23 12000 1052 59% 165 281.4 13 0.09 8.5% net.audio
24 11000 1043 66% 54 78.6 4 0.03 8.4% net.news
25 11000 1022 67% 122 122.0 11 0.04 8.3% net.wanted.sources
26 11000 1017 53% 41 55.1 3 0.02 8.2% net.consumers
27 11000 1001 53% 7 20.1 0 0.01 8.1% net.announce.arpa-int
28 11000 975 46% 7 18.0 0 0.01 7.9% mod.newprod
29 10000 925 58% 35 565.9 3 0.22 7.5% net.sources.mac
30 10000 920 45% 2 18.3 0 0.01 7.4% mod.os.unix
31 10000 915 56% 68 87.2 6 0.03 7.4% net.books
32 9900 905 63% 132 218.8 13 0.09 7.3% net.emacs
33 9900 900 58% 71 152.0 7 0.06 7.3% net.misc
34 9900 899 57% 95 134.3 9 0.05 7.3% net.lang
35 9800 895 62% 25 28.6 2 0.01 7.2% net.lan
36 9800 892 55% 150 181.3 15 0.07 7.2% net.cooks
37 9800 887 54% 135 486.0 13 0.19 7.2% mod.ai
38 9700 883 54% 40 69.9 4 0.03 7.1% net.invest
39 9600 876 57% 28 41.4 2 0.02 7.1% net.micro.68k
40 9500 861 55% 5 6.0 0 0.00 7.0% net.research
TOP 40 NEWSGROUPS IN ORDER BY PER-READER COST
+-- Estimated total number of people who read the group, worldwide.
| +-- Actual number of readers in sampled population
| | +-- Propagation: how many sites receive this group at all
| | | +-- Recent traffic (messages per month)
| | | | +-- Recent traffic (kilobytes per month)
| | | | | +-- Participation ratio
| | | | | | +-- Cost ratio: $US/month/reader
| | | | | | | +-- Share: % of newsreader
| | | | | | | | who read this group.
V V V V V V V V
1 44 4 1% 11 31.7 259 2.80 0.0% talk.religion.christi
2 1800 160 21% 450 1540.6 250 3.40 1.3% talk.religion.misc
3 1600 144 21% 317 1030.8 198 2.50 1.2% talk.politics.misc
4 55 5 0% 7 8.5 129 0.61 0.0% rec.arts.movies
5 1100 103 12% 137 354.2 124 1.30 0.8% misc.legal
6 5100 464 31% 620 1497.8 121 1.20 3.7% soc.singles
7 66 6 0% 7 9.2 108 0.55 0.0% rec.arts.sf-lovers
8 850 77 9% 90 155.6 105 0.72 0.6% sci.lang
9 55 5 0% 5 6.3 103 0.45 0.0% rec.aviation
10 1300 116 14% 128 225.9 98 0.68 0.9% sci.med
11 620 56 8% 51 29.4 82 0.19 0.5% misc.test
12 6700 608 44% 540 1994.2 80 1.20 4.9% net.micro.atari16
13 1800 163 16% 135 623.8 75 1.40 1.3% soc.culture.indian
14 1800 160 16% 135 316.4 75 0.69 1.3% misc.misc
15 4100 369 29% 301 441.8 73 0.42 3.0% talk.bizarre
16 4000 365 37% 295 534.1 73 0.52 2.9% net.sport.football
17 1100 103 12% 74 124.6 67 0.45 0.8% misc.kids
18 1400 131 11% 92 185.1 66 0.52 1.1% sci.math
19 4000 367 36% 260 417.2 65 0.41 3.0% net.sport.baseball
20 66 6 0% 4 4.5 64 0.27 0.0% rec.pets
21 8900 809 59% 534 862.3 60 0.38 6.5% net.sf-lovers
22 5000 454 40% 294 584.6 58 0.46 3.7% net.comics
23 9200 834 56% 521 2080.3 56 0.89 6.7% net.micro.amiga
24 1300 114 18% 72 319.4 56 0.97 0.9% talk.philosophy.misc
25 2600 237 25% 138 282.6 53 0.43 1.9% mod.music.gaffa
26 1600 148 18% 84 203.1 52 0.50 1.2% talk.abortion
27 2000 178 15% 98 92.2 49 0.18 1.4% misc.wanted
28 88 8 0% 4 16.1 48 0.72 0.1% rec.bicycles
29 9300 848 54% 428 650.7 46 0.27 6.9% net.auto
30 1300 114 12% 60 152.8 46 0.46 0.9% sci.physics
31 8900 809 54% 404 712.2 45 0.31 6.5% net.music
32 14000 1260 69% 622 2342.3 44 0.66 10.2% net.micro.pc
33 2100 193 19% 91 230.9 43 0.43 1.6% soc.motss
34 1500 141 14% 64 134.4 42 0.35 1.1% sci.astro
35 1400 125 16% 60 74.4 42 0.21 1.0% soc.culture.celtic
36 6500 589 50% 267 452.9 41 0.27 4.8% net.startrek
37 6300 576 48% 249 375.2 39 0.23 4.7% net.micro.apple
38 5300 482 41% 182 299.6 34 0.22 3.9% net.pets
39 5800 529 43% 191 354.3 33 0.24 4.3% net.aviation
40 4800 433 37% 162 252.5 33 0.21 3.5% net.ham-radio
TOP 40 NEWSGROUPS IN ORDER BY MESSAGES PER READER
+-- Estimated total number of people who read the group, worldwide.
| +-- Actual number of readers in sampled population
| | +-- Propagation: how many sites receive this group at all
| | | +-- Recent traffic (messages per month)
| | | | +-- Recent traffic (kilobytes per month)
| | | | | +-- Participation ratio
| | | | | | +-- Cost ratio: $US/month/reader
| | | | | | | +-- Share: % of newsreader
| | | | | | | | who read this group.
V V V V V V V V
1 14000 1260 69% 622 2342.3 44 0.66 10.2% net.micro.pc
2 9200 834 56% 521 2080.3 56 0.89 6.7% net.micro.amiga
3 6700 608 44% 540 1994.2 80 1.20 4.9% net.micro.atari16
4 1800 160 21% 450 1540.6 250 3.40 1.3% talk.religion.misc
5 5100 464 31% 620 1497.8 121 1.20 3.7% soc.singles
6 25000 2303 74% 114 1218.5 4 0.19 18.6% net.sources
7 1600 144 21% 317 1030.8 198 2.50 1.2% talk.politics.misc
8 8900 809 59% 534 862.3 60 0.38 6.5% net.sf-lovers
9 20000 1783 66% 24 807.7 1 0.16 14.4% mod.sources
10 25000 2307 64% 505 744.4 20 0.12 18.6% net.jokes
11 7000 640 45% 14 721.2 2 0.40 5.2% mod.mac.sources
12 8900 809 54% 404 712.2 45 0.31 6.5% net.music
13 15000 1361 73% 357 671.1 23 0.18 11.0% net.unix-wizards
14 9300 848 54% 428 650.7 46 0.27 6.9% net.auto
15 1800 163 16% 135 623.8 75 1.40 1.3% soc.culture.indian
16 13000 1139 61% 364 615.2 28 0.19 9.2% net.movies
17 5000 454 40% 294 584.6 58 0.46 3.7% net.comics
18 10000 925 58% 35 565.9 3 0.22 7.5% net.sources.mac
19 4000 365 37% 295 534.1 73 0.52 2.9% net.sport.football
20 14000 1268 63% 341 523.1 24 0.15 10.2% net.micro.mac
21 7500 686 48% 20 490.9 2 0.26 5.5% mod.mac
22 9800 887 54% 135 486.0 13 0.19 7.2% mod.ai
23 6500 589 50% 267 452.9 41 0.27 4.8% net.startrek
24 4100 369 29% 301 441.8 73 0.42 3.0% talk.bizarre
25 4000 367 36% 260 417.2 65 0.41 3.0% net.sport.baseball
26 16000 1469 72% 245 380.1 15 0.09 11.9% net.unix
27 6300 576 48% 249 375.2 39 0.23 4.7% net.micro.apple
28 14000 1232 63% 125 362.5 8 0.10 10.0% net.arch
29 5800 529 43% 191 354.3 33 0.24 4.3% net.aviation
30 1100 103 12% 137 354.2 124 1.30 0.8% misc.legal
31 7200 657 56% 91 333.5 12 0.18 5.3% mod.std.unix
32 3300 299 33% 20 326.6 6 0.39 2.4% mod.politics.arms-d
33 13000 1148 66% 198 322.9 15 0.10 9.3% net.lang.c
34 1300 114 18% 72 319.4 56 0.97 0.9% talk.philosophy.misc
35 1800 160 16% 135 316.4 75 0.69 1.3% misc.misc
36 5300 482 41% 182 299.6 34 0.22 3.9% net.pets
37 4700 431 42% 134 299.0 28 0.25 3.5% net.games.frp
38 8900 808 52% 205 297.9 23 0.13 6.5% mod.computers.vax
39 9300 845 64% 14 295.9 1 0.13 6.8% mod.newslists
40 15000 1407 65% 108 291.9 7 0.08 11.4% net.ai
BOTTOM 10 NEWSGROUPS IN ORDER BY POPULARITY
+-- Estimated total number of people who read the group, worldwide.
| +-- Actual number of readers in sampled population
| | +-- Propagation: how many sites receive this group at all
| | | +-- Recent traffic (messages per month)
| | | | +-- Recent traffic (kilobytes per month)
| | | | | +-- Participation ratio
| | | | | | +-- Cost ratio: $US/month/reader
| | | | | | | +-- Share: % of newsreader
| | | | | | | | who read this group.
V V V V V V V V
244 550 50 2% 2 1.3 5 0.01 0.4% news.misc
245 440 40 6% 8 10.0 19 0.09 0.3% sci.math.stat
246 420 38 5% 8 9.2 20 0.09 0.3% sci.bio
247 400 36 2% 1 0.6 3 0.01 0.3% rec.misc
248 88 8 0% 4 16.1 48 0.72 0.1% rec.bicycles
249 66 6 0% 7 9.2 108 0.55 0.0% rec.arts.sf-lovers
250 66 6 0% 4 4.5 64 0.27 0.0% rec.pets
251 55 5 0% 7 8.5 129 0.61 0.0% rec.arts.movies
252 55 5 0% 5 6.3 103 0.45 0.0% rec.aviation
253 44 4 1% 11 31.7 259 2.80 0.0% talk.religion.christi
Valid data received from these sites:
3comvax 3d.dec.com a60 aaec abnji ace.dec.com acetes adelie aero aero2
aiag.dec.com akgua akgub akguc akgud akov68.dec.com alberta alliant alv
amdahl amdcad ames argus arthur arthur.cs.purdue.edu ascvax asd.dec.com
astrovax atari athena aurora author.dec.com axis basser bcm5000
bemis.dec.com bene beno.css.gov bigbang bms-at bnl brand brspyr1 btnix
bu-cs bubba bucsb.bu.edu bucsd cadomin cae780 caip.rutgers.edu calay
calgary carmel cascade casee.dec.com castor.dec.com cavell cbosgd
ccvaxa celica.dec.com cgfsv1.dec.com cgl.ucsf.edu chalmers charlie
cheviot chinet ci-dandelion circe cisunx cit-vax clio clt.dec.com
cognos comet.dec.com concurrent.co.uk cookie.dec.com cooper cp1 cpro
cpsc53 cpw.columbia.edu crcge1 crin crvax1.dec.com cs.nott.ac.uk csadfa
csc02.dec.com csustan cuae2 curium.dec.com cuuxb cvl cwruecmp cxsea
darth dayton dciem dcl-csvax decuac decwet.dec.com decwrl desint
diamond.bbn.com dicome dievms.dec.com dinadan dione dlb dmcnh
dolphn.dec.com doshita down dregs.dec.com drillsys dukempd dycom
ector.cs.purdue.edu edison elbereth.rutgers.edu elroy elsie
elwood.dec.com ems endor eros eta ethos exodus.dec.com fai felix
fortune foxvax5 fritz ganash garfield gargoyle gatech genrad glacier
godot godzla.dec.com gould9 gouldsd grc97 grebyn gt-stratus h-sc4
h.cc.purdue.edu hao hc.dspo.gov hdsvx1 hercules hjuxa hpldora hscfvax
hutch i.cc.purdue.edu iapetus ihu1n ileaf im4u ima imagen imt3b2
infinet infopro iosg.dec.com ipso.oz iscuva isis isl istg.dec.com
ittvax j.cc.purdue.edu jasper jaws.dec.com jimi jon.dec.com jplgodo
k.cc.purdue.edu kaoa01.dec.com kirk.dec.com kodak kosman kpe
l.cc.purdue.edu labrea lando.dec.com lll-crg lll-lcc ludwig.dec.com
luke macbeth maccunix majestix masscomp maynard mcc-pp mcgill-vision
mck-csc me-ncr meccts medusa.dec.com midacs mips mirror mit-eddie
mit-trillian mks mntgfx moncol mordred mordred.cs.purdue.edu
mosaic.dec.com mss msudoc mtgzy mtgzz munsell myrias naakka
nandi.dec.com navajo nbires ncoast ncr-sd ncrcae nesterc nike noao
nogov.dec.com nonode.dec.com novavax nsc nssg.dec.com nttlab oblio
oblio.dec.com ocean oddjob ohgua ohgub ohguc oktext onecom opus orion
osiris panda pbhya penet percival phri phuxa phuxc pipa.dec.com pitt
pixar plus5 pogo polaris potomac princeton psivax ptsfa ptsfb ptsfc
ptsfd qantel qnda01 quad1 quoin.dec.com ra rainbo.dec.com
rangly.dec.com raster rayssd rdlvax reality1 regal.dec.com rhea.dec.com
rochester rocky rosevax rtech rti-sel saber samira sandia sandoz saturn
sauron scicom sdcsvax se-sd seismo shasta sicsten sigma soma spar
sphinx sphinx.dec.com sri-spam ssc-vax ssdevo.dec.com star.dec.com
strata.dec.com stride strshp.dec.com styx su-isl sunybcs teddy teklds
telesoft temvax termin tflop tilt tipple.dec.com tkov58.dec.com
tle.dec.com topaz.rutgers.edu trwhal tuck tucos turtlevax tut tutctl
tymix ucla-cs uiucuxa uiucuxc uiucuxe uiucuxf ujocs ukma umd-ua
umd5.umd.edu umn-cs unirot uqcspe.oz usc-oberon usceast ut-sally
utah-cs utah-gr utcs utcsri uwmacc vianet video.dec.com viking.dec.com
vilya vino.dec.com voder vogon.dec.com vu-vlsi vulcan walldata wang7
wanginst watale watarts watcal watcgl watdaisy watdcsu watdragon wateng
water watlion watmath watmum watnot watopt watpix watrose watvlsi well
wjh12 wolf wookie.dec.com wuphys xios yale yarra yetti yippee.dec.com
zeus zhora.dec.com
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EXPLANATION OF THE MEASUREMENTS AND STATISTICS
Survey data is taken by having one person at each site run a program called
"arbitron", which looks at the news or notes files and determines the
newsgroups that the user has read within a recent interval. To "read" a
newsgroup means to have been presented with the opportunity to look at at
least one message in it. Going through a newsgroup with the "n" key counts
as reading it. For a news site, "user X reads group Y" means that user X's
.newsrc file has marked at least one unexpired message in Y. If there is no
traffic in a newsgroup for the measurement period, then the survey will show
that nobody reads the group. For a notes site, "user X reads group Y" means
that user X has been in the notesfile with the sequencer in the last 14 days.
The "14 days" interval for notesfiles corresponds to "unexpired" for news.
The "arbitron" program is periodically posted to net.sources, or is available
from me (decwrl!reid). The notesfiles version of the program should be
available through standard notesfiles software distribution channels as well.
SITES SURVEYED IN THIS SAMPLE
"This Sample" means the set of sites that have sent in an arbitron report
within the past "Readership measurement interval" days. In every case the
most recent report from each site is used. At the moment, some of the
readership reports are several months old. In future postings those reports
will have expired and will not be included.
One might argue that the sample is self-selected, like the famous Literary
Digest Dewey-Truman election poll sample. It does in fact have a certain
self-selection factor in it, because we only get data from sites at which
someone participates in the survey. However, we do not require the
participation of every user at a site, only one user. The survey program
returns data for every user on the system on which it was run. Since there
are an average of 30 people per site reading news, there is a certain amount
of randomness introduced that way. Of course, the sample is biased in favor
of large sites (they are more likely to have a user willing to run the survey
program) and software-development-oriented sites (more likely to have a user
*able* to run the survey program). I intend to post, reasonably soon, some
breakdowns of statistics about the sites that have responded.
NETWORK SIZE
I determine the network size by looking at the set of sites that are
mentioned in the Path lines of news articles arriving at decwrl. This number
is consistently higher than the number of sites that posted a message (as
measured and posted from Seismo) because it includes passive sites that are
on the paths between posting sites and decwrl. Each month I store the names
of the hosts that are named that month, and for this report I used the past
7 months worth of data.
There are 4713 different sites in the Path lines of articles that
arrived at decwrl in the last 7 months. There are 6173 different sites in
the mod.map data, but mod.map includes every site that participates in uucp;
there is a considerable number of machines that exchange uucp mail but do not
get USENET. Of those 4713 sites, 60 (1%) are DEC E-net hosts not part of
uucp, and which therefore are not included in the 6173 figure.
Despite these various difficulties, I believe that 4800 is the best
estimate for the size of USENET. Because it is actually a measurement of the
number of sites that have posted a message or that are on the path to a site
that has posted a message, it will be slightly smaller than the number of
sites that actually read netnews. Any site that believes it is not being
counted can just ensure that it posts at least one message a year, so that
it will be counted.
NUMBER OF USERS
The number of users at each site is determined in a site-specific fashion.
Sometimes it is done by counting the number of user accounts that have
shells and login directories. Sometimes it is done by counting the number of
people who have logged in to the machine in some interval. Sometimes other
techniques are used. This number is probably not very accurate--certainly
not more accurate than to within a factor of two.
ESTIMATED TOTAL NUMBER OF PEOPLE WHO READ THIS GROUP, WORLDWIDE
There are two sources of error in this number. The number is computed by
multiplying the number of people in the sample who actually read the group by
the ratio of estimated network size to sample size. The estimated total can
therefore be biased by errors in the network size estimate (see above) and
also by errors in the determination of whether or not someone reads a group.
Assuming that "reading a group" is roughly the same as "thumbing through a
magazine", in that you don't necessarily have to read anything, but you have
to browse through it and see what is there, then the measurement error will
come primarily from inability to locate .newsrc files, which can either be
protected or moved out of root directories. There is no way of measuring the
effect on the measurements from unlocated .newsrc files, but it is not likely
to be more than a few percent of the total news readers.
MESSAGES PER MONTH AND KILOBYTES PER MONTH
Traffic is measured at decwrl, in Palo Alto, California. Any message that has
arrived at decwrl within the last "Traffic measurement interval" days is
counted, regardless of when it was posted. Monthly rates are computed by
taking the total traffic, dividing by the number of days in the traffic
measurement interval, and multiplying by 30. Decwrl runs 2.10.3 news, which
does not store the "Date-Received", "Relay-version" or "Posting-version"
header lines; the amount of space occupied at your site might be higher, and
the number of bytes transmitted between machines is probably higher. By
definition this number is correct, because it is an exact measurement, but it
may differ from the traffic at your site by as much as 15% due to timing
differences and news version differences. Timing differences will be random,
but will average out in the long run. News version differences will cause a
systematic error that is additively uniform across all newsgroups, and which
therefore does not significantly affect ratios.
If a message is crossposted to several groups simultaneously, it is charged
only to the first-named group in the list.
PARTICIPATION RATIO: MESSAGES per MONTH per 1000 READERS
This number is exactly what it says: the number of messages per month in
that newsgroup, divided by the number of 1000 readers. It is an indication
of how involved the readers of the group are in the traffic, of whether they
are mostly listeners or mostly talkers. Its accuracy is limited by the
accuracy of its two components. The messages per month figure is exact; the
reader count is only as accurate as the network size estimate, which is in
worst case accurate to 40%. Therefore you should treat this number as having
an error margin of plus or minus 40%. However, ratios between participation
ratios for different newsgroups are quite accurate, since the network-size
component divides out.
COST RATIO: DOLLARS PER MONTH PER READER
The most controversial field in the survey report is the "$US per month per
reader". It is the estimated number of dollars that are being spent on
behalf of each reader, worldwide, on telephone costs to transmit this
newsgroup. The cost ratio does not include the cost of disk storage to store
the news or of computer time to process it; both of those are assumed to be
free.
The cost ratio is computed as follows:
$US/month/reader = ($USPerMonthPerSite * numberOfSites) / numberOfReaders
$USPerMonthPersite = KBytesTrafficPerMonth * $USPerKByte
$USPerKByte = ($USperMinute / KBytesPerMinute) * (1 - CompressionFactor)
$USperMinute = 0.10 [ten cents per minute avg phone cost]
KBytesPerMinute = 60 * BytesPerSecond / 1000
BytesPerSecond = 100 [average transfer rate over 1200-baud line]
CompressionFactor = 0.4 [40% compression is typical for netnews]
Combining all these gives
$USPerMonthPersite =
KBytesTrafficPerMonth * (0.10 / 6) * (1 - 0.4)
= KBytesTrafficPerMonth / 100
Therefore:
$US/month/reader =
(KBytesTrafficPerMonth * numberOfSites) / (100 * numberOfReaders)
The accuracy of this number is in fact better than the accuracy of the
participation ratio, because the source of error--the network size
estimate--is present both in the numerator and the denominator, and therefore
cancels out. The primary source of bias in this number comes from the bias in
the "estimated number of readers, worldwide", which is described above. Treat
this value as being accurate to within about 25%.
SITE PARTICIPATION
I would like to receive data from every site on USENET. The arbitron programs
(posted to net.sources along with this report) work on news 2.9 and 2.10.[1-3]
and on many versions of notesfiles.
Brian Reid
DEC Western Research Laboratory, Palo Alto CA
reid@decwrl.DEC.COM
{ihnp4,allegra,decvax,ucbvax,sun,glacier}!decwrl!reid