Here's a list of topics for a history of the net. Not all these are in the right order. I haven't included everything here. If you know an event that's not super-specific to a group, and you think was of prominent importance to the structure of the net, MAIL that to me.

The human-nets digest on the arpanet (and sf-lovers)
Plato and CBBS
The uucp program
Notesfiles at U of Ill.
Compuserve and The Source
The A-news system (Bellovin, Truscott of Duke)
Usenix 1980, Duke invites sites to join usenet.
Bell labs 'research' creates first cross country links
The first newsgroups
- "NET." groups (uppercase)
- "fa" groups
- "net." groups (renamed)
- The mistake of net.general
- First nontech groups, net.jokes, net.rumor
Creating groups by typo or whim - net.joke, net.bizarre, net.flame, net.gdead, net.wobegon and others
Net goes international (Canada) (Spencer, Templeton)
The B news software (Horton, Glickman)
Pathalias software (Bellovin)
Decvax and Bill Shannon's contribution
Imminent death of net predicted
Chain letters over the net.
AT&T's contribution (allegra, ihnp4 etc.)
Widespread net growth and international growth
Forged article critical of Unix (1981)
K News (proposal)
Domain style naming (Postel et al)
The net.jokes.q creation and deletion
Formation of the "Backbone"
net.women.only experiment
Arpa mailing lists merge with usenet groups. (Erik Fair & UCB)
Subgroups to divert traffic: net.startrek, net.abortion, source code discussion
Imminent death of net predicted
Hoaxes etc. (kremvax, walldrug) -- Landon Noll
The re-emergence of mailing lists
UUCP Map project (Horton et al)
net.columbia and naming debates
The emergence of voting for creating newsgroups
Notesfiles users join in with USENET.
RN & Kill files (Wall)
News batching and compression
Checkgroups messages (Spafford)
THe problems with the old releases of B news
Line Eater Bug
Moderated newsgroups:
- mod.announce
- mod.newprod and commercial information on the net
netnews software implemented on VM (IBM Mainframes)
Stargate (Weinstein)
NSA Baiting in messages
Imminent death of net predicted
Big Net personal fights
- some result in lawsuit threats (Mark Ethan Smith)
- some result in people being bounced temporarily from the net (Maroney)
- some result in people being removed permanently.
The great renaming (Adams, Von Rospach, et al)
The merging of moderated groups into the hierarchy.
The decline in propagation for groups outside of "comp" and "news"
Creation of rec.humor.funny (first ultra-moderated non-mailing-list) (Templeton)
Battle over the expiry dates on rec.mag.otherrealms. (Von Rospach)
The attempt to form comp.protocols.tcp-ip.eniac. (Webber)
Monthly postings, newuser group, commonly asked questions.
Imminent death of net predicted
The misnaming of soc.culture.china -> 30 day voting time.
Attempt to remove talk.bizarre from the net for the "VOLUME,VOLUME,VOLUME" game.
"jj@portal" (Rob Noha) begs for money on the net.
General problems with Portal, and the issue of pay-for-access net sites.
Attempts to form groups for drugs and sex.
Creation of the "alt" hierarchy. (Gilmore, Reid, Gordon Moffett)
UUCP project and .US domain. (Gilmore, Horton)
Arbitron news statistics (Reid)
Imminent death of net predicted
Telebit releases the Trailblazer.
UUNET arrives (Adams) (Seismo fades)
Internet & TCP/IP begins to pervade the net. The backbone begins to fade. (Later the backbone mailing list even goes)
NNTP causes news to propagate too fast.
PC-Pursuit (Telnet) flat rate off-peak modem calls
Reliable links to Europe
Crazy creation of groups in the alt hierarchy. (Weiner)
alt.gourmand kept rather than being renamed. (Reid)
AT&T decides not to forward mail.
"biz" and "inet" hierarchies. "Gnu" hierarcy.
Imminent death of net predicted
comp.sys.next violates voting rules
AT&T complains about source code on Killer, shuts it off temporarily(?)
comp.binaries.ibm.pc goes to 8 megs/month, gets moderated in first (and only) moderator election. (Dhesi)
The forming of comp.society.women (proposed as comp.women) (Roberts)
Oct/88 Internet Worm (perhipheral to usenet)
Nov/88 The battle over rec.humor.funny (Templeton, Richmond)
C News (Spencer, Collyer)
NN (actually started earlier)
B News 3.0 (Raymond)
alt.fusion, sci.physics.fusion
More rec.humor.funny -- Jokebook, Expansion to GEnie, Denninger's vote
Aquaria alt, rec, sci (sci.skeptic?)
Battles about naming, Australian voting etc.
shareware on usenet
flow mapping (Reid)
bitnet merging into USENET, more newsreaders etc.
more moderator copyright (telecom, sci.med.aids)
June 89/ClariNet (the first dot-com)
In Moderation Network (Goodfellow)
Posting of this history coins phrase, "imminent death of net predicted."
More forgery
alt.sex, alt.sex.bondage and "Cindy's Torment" -- cutoff at U of T, etc.
AlterNet, NYSERNET/PSI, NSFNet, FARRnet
Confiscation of USENET sites involved with phrack.
EUNet and its policies (pay for feed, limit feed, not all groups)
rec.arts.erotica (which later became dormant)
Alt explosion, more alt bannings, rise of alt.sex
trial newsgroups
USENET over 10 megs/day
BIFF and further use of forgery, multiple biffs, serious forgery
Talk of a secure net
Alt.sex becomes #1 read USENET group (falls back to #2 one month later)
comp.unix.sco -- debate over corporations and the net (yet again)
June 90/"Internet Porno Ring"/Houston Chronicle
TRN threaded version of RN newsreader
Dynamic usenet feeding
Founding of EFF
ANS & More on commercialization of the internet
Newsgroup reorganizations (mac, unix, ibm)
Mar 91/misc.activism.general, political groups
Mar 91/C news cracks down on headers
May 91/AT&T reader gets fired for posting confidential info to comp.dcom.telecom
A real kremvax
Usenet over 20 megs/day
May 91/Trial hierarchy in trouble
Aug 91/sf-lovers reorg fails, claims of vote interference, counter campaigning
Aug 91/Question on large (one megabyte) articles and their validity.
Aug 91/Net has small role in Soviet Coup
Sep 91/Trial hierarchy change vote
news.answers group
More software prloliferates -- trn, trumpet for PCs, bbs gateways.
Jan/92 Internet commercializations battles, ANS vs. others
Early92 Sterling offers net archives via CD Rom, NetGems
Jun/92 Alt.sex.bondage banned UManitoba, elsewhere
Jul/92 Globe and mail does long feature on alt.sex.bondage
Jun/92 Somebody posts hundreds of bogus cancels, anything crossposted.
Jul/92 Copyright model of USENET battle flares again
Oct/92 Somebody e-mails almost every usenet poster
Nov/92 Postings of gifs of children, FBI investigation at Cornell
Mar/92 Steve Jackson BBS case against secret service won.
Mar/92 General anonymous posting server for all groups
Mar/92 Auto cancel for anon postings AARM (Depew), buggy software
Dec/92 Attempt to move alt.folklore.computer into mainstream fails resoundingly [Brader]
Apr/93 Gene Spafford withdraws from many active years on the net
??/93 War with moderator of comp.dcom.telecom group over moderation, new
group comp.dcom.telecom.tech defeated, then wins on appeal.
Usenet over 100 megs/day, over 51% of it is ALT
Jan/94 Christ is coming -- posted to every newsgroup (first spam)
Apr/94 Student at MIT runs alleged pirate BBS, charged with conspiracy
Mid/94 The World Wide Web starts to grow as internet browsing application
Apr/94 Canter and Siegel post immigration ad solicitation to every newsgroup
May/94 Media continues to write a lot about the net.
Aug/94 US hierarchy proposed and stamped on
Nov/94 Canter and Siegel publish book on how to guerilla market on the net
Dec/94 Microsoft buys Catholic Church hoax gets attention of real world
Dec/94 Publishers of NetChat robo-post to market their book.
Jan/95 Web readers like netscape become decent newsreaders
Apr/95 News.admin is reorganized
Apr/95 Usenet is over 200 megs/day

This only touches some groups. Other groups all have their histories of battles, common questions, hoaxes, problem users and attempts to split the group. Groups that probably deserve a section are:

sf-lovers (with drwho and startrek)
women
men
sources (of various sorts)
binaries (of various sorts)
unix groups
music.misc
politics, philosophy and religion
.. and many others ..
news.*

A history of the net should also have chapters on...

Groups that never made it
UUPC, Xenix and the arrival of small machines
Acroynyms, Culture and smileys
Usenix and USENET