reid@decwrl.UUCP (06/01/86)
USENET READERSHIP SUMMARY REPORT for May 86
This is a monthly posting from the USENET 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
Brian Reid
----------------------------------------------------------------------------
Duplicated data for amdahl
OVERALL SUMMARY:
This Estimated
Sample for entire net
Sites: 392 2352
Fraction reporting: 16.67% 100.00%
Users with accounts: 48443 290000
Netreaders: 10967 65000
Average readers per site: 28
Percent of users who are netreaders: 22.64%
Average traffic per day (megabytes): 1.908
Average traffic per day (messages): 886
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
| | +-- Recent traffic, in messages per month.
| | | +-- Recent traffic, in kilobytes per month.
| | | | +-- Participation ratio: msgs/month/Krdrs
| | | | | +-- Cost ratio: $US/month/reader
| | | | | | +-- Rating: % of all users who
| | | | | | | read this group.
| | | | | | | +-- Share: % newsreaders
| | | | | | | | who read this group.
V V V V V V V V
1 15000 2842 7 14.2 0 0.00 5.9% 25.9% net.announce
2 15000 2712 35 88.6 2 0.02 5.6% 24.7% net.general
3 14000 2619 928 1098.5 66 0.31 5.4% 23.9% net.jokes
4 12000 2181 137 2070.2 11 0.68 4.5% 19.9% net.sources
5 11000 2015 8 71.8 0 0.03 4.2% 18.4% net.announce.newuse
6 9200 1695 102 226.7 11 0.10 3.5% 15.5% net.jobs
7 8900 1656 45 1038.3 5 0.46 3.4% 15.1% mod.sources
8 7400 1378 8 23.6 1 0.01 2.8% 12.6% mod.newprod
9 7300 1346 277 468.4 37 0.25 2.8% 12.3% net.unix
10 7200 1330 251 652.5 34 0.36 2.7% 12.1% net.micro
11 7000 1296 452 728.7 64 0.41 2.7% 11.8% net.rumor
12 7000 1288 314 605.7 44 0.34 2.7% 11.7% net.unix-wizards
13 6700 1234 191 209.5 28 0.12 2.5% 11.3% net.wanted
14 6600 1224 1098 1900.1 166 1.10 2.5% 11.2% net.singles
15 6500 1208 15 142.1 2 0.09 2.5% 11.0% net.sources.games
16 6200 1154 488 1052.2 78 0.67 2.4% 10.5% net.micro.pc
17 6200 1151 308 537.1 49 0.34 2.4% 10.5% net.audio
18 6100 1136 2 11.6 0 0.01 2.3% 10.4% mod.os.unix
19 6100 1132 45 71.8 7 0.05 2.3% 10.3% net.sources.bugs
20 6100 1124 424 725.7 69 0.47 2.3% 10.2% net.lang.c
21 6100 1124 17 35.0 2 0.02 2.3% 10.2% net.announce.arpa-i
22 6000 1117 150 269.4 25 0.18 2.3% 10.2% net.arch
23 5900 1089 381 602.4 64 0.40 2.2% 9.9% net.movies
24 5600 1040 532 920.8 95 0.64 2.1% 9.5% net.micro.mac
25 5500 1015 91 179.6 16 0.13 2.1% 9.3% net.ai
26 5400 1002 67 94.2 12 0.07 2.1% 9.1% net.sources.d
27 5400 1000 281 443.7 52 0.32 2.1% 9.1% net.consumers
28 5300 985 64 180.1 12 0.13 2.0% 9.0% net.graphics
29 5200 968 181 247.0 34 0.19 2.0% 8.8% net.cooks
30 5200 956 221 370.5 42 0.28 2.0% 8.7% net.misc
31 5100 938 191 357.8 37 0.27 1.9% 8.6% net.news
32 5000 926 312 708.9 62 0.56 1.9% 8.4% net.women
33 4900 902 34 59.8 6 0.05 1.9% 8.2% net.columbia
34 4800 881 665 1140.2 138 0.93 1.8% 8.0% net.music
35 4700 878 50 797.3 10 0.66 1.8% 8.0% mod.sources.doc
36 4700 875 42 65.0 9 0.05 1.8% 8.0% net.lang
37 4700 867 12 17.7 2 0.01 1.8% 7.9% net.research
38 4600 852 235 524.0 51 0.45 1.8% 7.8% net.space
39 4600 850 111 115.8 24 0.10 1.8% 7.8% net.wanted.sources
40 4600 845 25 36.2 5 0.03 1.7% 7.7% net.micro.68k
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
| | +-- Recent traffic, in messages per month.
| | | +-- Recent traffic, in kilobytes per month.
| | | | +-- Participation ratio: msgs/month/Krdrs
| | | | | +-- Cost ratio: $US/month/reader
| | | | | | +-- Rating: % of all users who
| | | | | | | read this group.
| | | | | | | +-- Share: % newsreaders
| | | | | | | | who read this group.
V V V V V V V V
1 2800 526 1111 2661.2 396 3.70 1.1% 4.8% net.politics
2 950 175 252 636.8 266 2.60 0.4% 1.6% net.politics.theory
3 1500 278 214 972.0 142 2.50 0.6% 2.5% net.religion.christ
4 2000 373 427 1192.0 213 2.30 0.8% 3.4% net.philosophy
5 4600 843 88 2269.4 19 1.90 1.7% 7.7% net.sources.mac
6 2000 369 227 801.8 113 1.60 0.8% 3.4% net.religion
7 6600 1224 1098 1900.1 166 1.10 2.5% 11.2% net.singles
8 2800 517 394 759.4 140 1.10 1.1% 4.7% net.micro.atari16
9 1500 282 114 381.0 76 1.00 0.6% 2.6% net.religion.jewish
10 4500 835 651 1076.9 144 0.94 1.7% 7.6% net.auto
11 4800 881 665 1140.2 138 0.93 1.8% 8.0% net.music
12 4200 778 657 978.3 156 0.91 1.6% 7.1% net.sf-lovers
13 4400 821 464 908.2 105 0.81 1.7% 7.5% net.micro.amiga
14 2200 412 234 452.6 106 0.81 0.9% 3.8% net.comics
15 2100 396 34 432.8 16 0.81 0.8% 3.6% mod.music
16 1700 306 115 340.8 68 0.79 0.6% 2.8% net.origins
17 4500 833 435 880.4 96 0.77 1.7% 7.6% net.news.group
18 4300 790 422 808.9 98 0.74 1.6% 7.2% net.followup
19 2300 431 184 419.8 80 0.72 0.9% 3.9% net.games.frp
20 1700 316 124 302.5 73 0.70 0.7% 2.9% net.abortion
21 3200 600 400 566.3 124 0.69 1.2% 5.5% net.startrek
22 12000 2181 137 2070.2 11 0.68 4.5% 19.9% net.sources
23 6200 1154 488 1052.2 78 0.67 2.4% 10.5% net.micro.pc
24 4700 878 50 797.3 10 0.66 1.8% 8.0% mod.sources.doc
25 810 150 81 136.8 100 0.66 0.3% 1.4% net.consumers.house
26 5600 1040 532 920.8 95 0.64 2.1% 9.5% net.micro.mac
27 2300 423 158 375.9 68 0.64 0.9% 3.9% net.motss
28 1800 328 151 289.3 84 0.63 0.7% 3.0% net.sport.hoops
29 3300 610 354 504.5 107 0.60 1.3% 5.6% net.tv
30 590 110 67 88.7 113 0.59 0.2% 1.0% net.rec.drugs
31 5000 926 312 708.9 62 0.56 1.9% 8.4% net.women
32 2300 425 137 317.4 59 0.54 0.9% 3.9% net.bio
33 1700 310 118 233.4 69 0.54 0.6% 2.8% net.nlang.india
34 3200 599 208 416.7 65 0.51 1.2% 5.5% net.kids
35 3400 637 244 430.9 71 0.50 1.3% 5.8% mod.computers.vax
36 3600 671 228 449.1 63 0.49 1.4% 6.1% net.sci
37 6100 1124 424 725.7 69 0.47 2.3% 10.2% net.lang.c
38 8900 1656 45 1038.3 5 0.46 3.4% 15.1% mod.sources
39 4600 852 235 524.0 51 0.45 1.8% 7.8% net.space
40 3000 558 190 342.9 63 0.45 1.2% 5.1% mod.protocols.tcp-i
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
| | +-- Recent traffic, in messages per month.
| | | +-- Recent traffic, in kilobytes per month.
| | | | +-- Participation ratio: msgs/month/Krdrs
| | | | | +-- Cost ratio: $US/month/reader
| | | | | | +-- Rating: % of all users who
| | | | | | | read this group.
| | | | | | | +-- Share: % newsreaders
| | | | | | | | who read this group.
V V V V V V V V
1 2800 526 1111 2661.2 396 3.70 1.1% 4.8% net.politics
2 950 175 252 636.8 266 2.60 0.4% 1.6% net.politics.theory
3 2000 373 427 1192.0 213 2.30 0.8% 3.4% net.philosophy
4 6600 1224 1098 1900.1 166 1.10 2.5% 11.2% net.singles
5 4200 778 657 978.3 156 0.91 1.6% 7.1% net.sf-lovers
6 4500 835 651 1076.9 144 0.94 1.7% 7.6% net.auto
7 1500 278 214 972.0 142 2.50 0.6% 2.5% net.religion.christ
8 2800 517 394 759.4 140 1.10 1.1% 4.7% net.micro.atari16
9 4800 881 665 1140.2 138 0.93 1.8% 8.0% net.music
10 3200 600 400 566.3 124 0.69 1.2% 5.5% net.startrek
11 2000 369 227 801.8 113 1.60 0.8% 3.4% net.religion
12 590 110 67 88.7 113 0.59 0.2% 1.0% net.rec.drugs
13 3300 610 354 504.5 107 0.60 1.3% 5.6% net.tv
14 2200 412 234 452.6 106 0.81 0.9% 3.8% net.comics
15 4400 821 464 908.2 105 0.81 1.7% 7.5% net.micro.amiga
16 810 150 81 136.8 100 0.66 0.3% 1.4% net.consumers.house
17 4300 790 422 808.9 98 0.74 1.6% 7.2% net.followup
18 4500 833 435 880.4 96 0.77 1.7% 7.6% net.news.group
19 5600 1040 532 920.8 95 0.64 2.1% 9.5% net.micro.mac
20 1800 328 151 289.3 84 0.63 0.7% 3.0% net.sport.hoops
21 2300 431 184 419.8 80 0.72 0.9% 3.9% net.games.frp
22 6200 1154 488 1052.2 78 0.67 2.4% 10.5% net.micro.pc
23 1500 282 114 381.0 76 1.00 0.6% 2.6% net.religion.jewish
24 1700 316 124 302.5 73 0.70 0.7% 2.9% net.abortion
25 2600 475 188 246.9 72 0.37 1.0% 4.3% net.pets
26 3400 637 244 430.9 71 0.50 1.3% 5.8% mod.computers.vax
27 6100 1124 424 725.7 69 0.47 2.3% 10.2% net.lang.c
28 1700 310 118 233.4 69 0.54 0.6% 2.8% net.nlang.india
29 2300 423 158 375.9 68 0.64 0.9% 3.9% net.motss
30 1700 306 115 340.8 68 0.79 0.6% 2.8% net.origins
31 14000 2619 928 1098.5 66 0.31 5.4% 23.9% net.jokes
32 3100 573 205 263.4 66 0.33 1.2% 5.2% net.games.hack
33 3200 599 208 416.7 65 0.51 1.2% 5.5% net.kids
34 1400 261 91 126.2 65 0.35 0.5% 2.4% net.micro.atari8
35 7000 1296 452 728.7 64 0.41 2.7% 11.8% net.rumor
36 5900 1089 381 602.4 64 0.40 2.2% 9.9% net.movies
37 3600 671 228 449.1 63 0.49 1.4% 6.1% net.sci
38 3000 558 190 342.9 63 0.45 1.2% 5.1% mod.protocols.tcp-i
39 5000 926 312 708.9 62 0.56 1.9% 8.4% net.women
40 1300 241 78 55.5 60 0.17 0.5% 2.2% net.test
BOTTOM 10 NEWSGROUPS IN ORDER BY POPULARITY
+-- Estimated total number of people who read the group, worldwide.
| +-- Actual number of readers in sampled population
| | +-- Recent traffic, in messages per month.
| | | +-- Recent traffic, in kilobytes per month.
| | | | +-- Participation ratio: msgs/month/Krdrs
| | | | | +-- Cost ratio: $US/month/reader
| | | | | | +-- Rating: % of all users who
| | | | | | | read this group.
| | | | | | | +-- Share: % newsreaders
| | | | | | | | who read this group.
V V V V V V V V
213 1000 194 4 9.4 4 0.04 0.4% 1.8% net.nlang.africa
214 950 175 252 636.8 266 2.60 0.4% 1.6% net.politics.theory
215 940 174 7 12.0 7 0.05 0.4% 1.6% net.nlang.greek
216 810 150 81 136.8 100 0.66 0.3% 1.4% net.consumers.house
217 590 110 67 88.7 113 0.59 0.2% 1.0% net.rec.drugs
218 460 86 10 17.4 21 0.15 0.2% 0.8% net.politics.terror
219 450 84 1 4.0 3 0.03 0.2% 0.8% mod.amiga
220 240 44 2 4.5 11 0.07 0.1% 0.4% net.micro.ns32k
221 210 39 11 10.4 54 0.19 0.1% 0.4% mod.computers.massc
222 160 29 1 1.1 8 0.03 0.1% 0.3% net.house
Valid data received from these sites:
3comvax aaec acetes adobe aero akgua akgub akguc alberta alv amdahl
amdcad amdimage arran.tcom.stc.co.uk arrow ascvax astroatc astrovax
atari athena aurora basser bdmrrr bene bentley birtch bocar boring
brand btnix burl bute.tcom.stc.co.uk cadomin caip.rutgers.edu calma
carmel cascade cavell cbosgd cca ccvaxa celerity chalmers cheviot
chinet chronon circe cod cogsci.berkeley.edu columbia cooper cord
csee-vax csi csib cuae2 cuuxb cvl cxsea cybvax0 dalcs davinci
dec-2littl dec-7618 dec-ace dec-akov68 dec-amber dec-angora dec-anyway
dec-argus dec-avanti dec-babel dec-bagels dec-bartok dec-beorn dec-beta
dec-bigalo dec-blott.uucp dec-boves dec-cadvax dec-casv01 dec-celica
dec-clt dec-cmkrnl dec-comet dec-comet2 dec-crvax1 dec-curie dec-curium
dec-dairy dec-delni dec-derep dec-ditto dec-dosadi dec-dregs dec-dssdev
dec-dvinci dec-ecadjr dec-elwood dec-enet dec-euclid dec-exodus
dec-fakehosts dec-fremen dec-gallo dec-gaynes dec-genral dec-glory
dec-gndzro dec-gramps dec-grofe dec-grok dec-highfi dec-hydra dec-ink
dec-iosg dec-jon dec-kirk dec-koning dec-latour dec-logic dec-ludwig
dec-lymph dec-miles dec-mlokai dec-mosaic dec-mradm dec-mrmfg3
dec-mtblue dec-netwrk dec-nimbus dec-nonode dec-nova dec-nutmeg
dec-oblio dec-oracle dec-osav01 dec-parrot dec-parvax dec-patois
dec-pipa dec-pisces dec-pldvax dec-quoin dec-rainbo dec-rangly
dec-raven1 dec-rhea dec-roxie dec-shorty dec-star dec-stoli dec-tallis
dec-tkov58 dec-tle dec-tonto dec-trco01 dec-ultra dec-vaxwrk dec-verdi
dec-wizdom dec-yogi decwrl desint desoto diablo dicome dione down
drexel edison edsel elsie eros felix fluffy foxvax5 fritz frog
frog.nosc.mil frog.nosc.mil ganash garfield.columbia.edu garfield.mun
gatech gcc-milo genrad gitpyr glacier glimmer gondor gould9 greg
grkermi gt-oscar gt-stratus hammer handel harvard hercules ho95e hocad
hoptoad hudson ia-sun2 iapetus icom ihu1n im4u imagen imt3b2 imt3b2
infinet infopro investor ipso iscuva ishtar jasper jplgodo kepler
kestrel killer kodak kontron kosman labrea ll-vlsi lll-crg lll-lcc
lmi-ang lmi-angel lsuc luke macbeth masscomp mcc-pp mcgill- mck-csc
meccts medea megaron mhuxh midacs mips mirror mit-eddie mnetor moncol
mordred msudoc mtgzy mtgzz mtu mtung mtunh muddcs mulga munnari myrias
navajo nbires ncoast nmtvax noao novavax nsc oberon ocean octopus
oddjob ohgua onecom opus orstcs osiris otto paisley panda parcvax
pembina peregrine philabs phri phuxa phuxc pierce plooba plus5 pogo
potomac princeton prism psivax psuvax1 pucc-h pucc-i pucc-j pucc-k
pyramid ra rayssd reed ritcv rose3 rsch saber sandia saturn sauron
scicom se-sd seismo sems sfmag sfsup shasta sigma sneaky sneezy spastic
stat-l stride stsci styx su-isl su-russell suadb tahoe talcott teddy
tekchips tekcrl tekig5 teklds tflop tikal tilt titn topaz.rutgers.edu
trillian tucos tulane turtlevax tut twitch tymix ucbvax.berkeley.edu
ucsfcgl uiucuxa uiucuxc uiucuxe uiucuxf ukma ulowell umd-cs umd-ua
unmvax unrvax usc-obe ut-sally utah-cs utah-gr utcs uwslh vianet voder
vu-vlsi vulcan walldata wang7 wanginst watarts watcgl watdais watdaisy
watdcsu watdrag watdragon wateng water watlion watmath watmum watnot
watpix watrose watvlsi well wicat yale yetti zeus zinfandel
------------------------------------------------------------------------------
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 40 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.
There are 2352 different sites in the Path lines of articles that
arrived at decwrl in the last month. There are 3819 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 2352 sites, 100 (4%) are DEC E-net hosts not part of
uucp. The DEC E-net participation in USENET complicates the statistics,
because we have 100% data for readership of USENET inside the DEC-Enet,
which makes extrapolating less accurate.
Despite these various difficulties, I believe that 2352 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 month, 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. I sampled 13 machines recently
and found only 2 users out of 715 who were actually news readers but whose
.newsrc file was not in their root directory. From this I have concluded that
the problem is not worth worrying about, since the error in network size
estimation will totally dominate it.
MESSAGES PER MONTH AND KILOBYTES PER MONTH
Traffic is measured at decwrl. 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 uniform across all newsgroups, and which therefore does not affect ratios.
Crossposted messages are tallied in all groups to which they are crossposted.
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 program
works on news 2.9, 2.10.1, and 2.10.2; Rich Salz has a version that works on
notesfiles.
Brian Reid
DEC Western Research Laboratory, Palo Alto CA
reid@decwrl.DEC.COM
{ihnp4,allegra,decvax,ucbvax,sun,glacier}!decwrl!reid