This began on March 25, 1995. A little later (May 1, 1995), an Invitation To The Patterns List caused an increase in participation. Growth has continued since then, to the point where the average number of new pages ranges between 5 and 12 per day.
Wards Wiki Tenth Anniversary occurred on March 25, 2005. At that time, we had about 30690 pages.
This is the first ever wiki site, founded as an automated supplement to the Portland Pattern Repository. The site was immediately popular within the pattern community, largely due to the newness of the Internet and a good slate of Invited Authors. The site was, and remains, dedicated to People Projects And Patterns.
I created the site and the Wiki Wiki Web machinery that operates it. I chose wiki-wiki as an alliterative substitute for quick and thereby avoided naming this stuff quick-web. Read more about etymology here: c2.com 
. An early page, Wiki Wiki Hyper Card, traces wiki ideas back to a Hyper Card stack I wrote in the late 80's. This same stack, by the way, spawned Crc Cards. I've reconstructed the Wiki Design Principles I applied at the time. Read more on the name here: c2.com .
Patrick Mueller wrote probably the first Wiki Wiki Clone, choosing the Rexx Language as a convenient vehicle for a night's work. I soon wrote a version of wiki that could host its own source code and announced Wiki Wiki Goes Public. Rather than fold changes back into my editable version, implementers chose to distribute their modifications on their own sites and boast of the many features they had added, accepting raw HTML being the most common one.
It has been claimed by some that the ideas that led to the Wiki concept have their origins (see: Wiki Wiki Origin) in the ZOG database system effort, first materialized at Carnegie-Mellon University in 1972.
Landmark changes to the Wiki script - approximate dates; please put correct dates if you know them.
1996 Edit Copy
1998 Perl5 dbm binding
1999 Denial-of-service protection logic
1999 Remote index for search
2000 Update conflict detection (Edit Conflict Resolution)
2000 User Name
2000 Quick Changes
2000 New Notification
2000 Like Pages, Visual Tour
2000 Page Deletion
2001 Sister Sites
2001? Minor Edit checkbox, to direct the changes to Recent Edits instead of Recent Changes
2002? Page History - a far more powerful tool than Edit Copy
2002 Abandoned dbm (see More About The Database)
2004/Feb Recent Posts
2004/Oct Minor Edits checkbox removed (see Minor Edits Disabled Discussion)
2004/Oct New Recent Changes introduced (see New Recent Changes Discussion)
2005 Edit Code Word requirement added
2005/June Google Hates Wiki, due to traffic throttling for spam avoidance
2006/May Wiki moves to a faster server and standardizes on Utf Eight
c2.com
2007/June Edit Text icon () added
2007/Oct Recent Posts removed
2007/Oct Wiki is becoming a One Pile Filing System
2007/Oct Google Loves Wiki again
Ok. But when does Recent Changes function appear?
The Recent Changes page leads to a meandering discourse dubbed Things On Wikis Mind. Those who follow submissions closely are dubbed Recent Changes Junkies. Even without this effect, this site has been known as a definitive site for information on varying subjects (again, approximate dates)...
Things this site has been known as a definitive site for
1995 patterns, their sources and application
1996 general design, architecture, methods
1997 people and organizational aspects of programming
1998 Extreme Programming
2000 wiki itself
2003 wiki, sociology, meta*
2005 vandalism and subsequent headaches
From the beginning, wiki was intended to index itself. Or, more correctly, wiki visitors were supposed to evolve into Volunteer Housekeepers. This is one reason that Recent Changes has never automatically pruned itself. A variety of indexing innovations have been introduced and maintained by the community.
Innovations introduced and maintained by the community
1995 Recent Visitors, People Index
1996 Wiki Categories
1997 Road Maps
1999 Change Summary (discontinued, but led to Quick Changes)
1999 Random Pages
1999? Changes In pages started. (Not So Recent Changes was out of hand and kept getting corrupted.)
2000 Search Helper
I occasionally suggest how this site should be used. My Good Style suggestions have been here since the beginning and are linked from the edit page should anyone forget. I have done my best to discourage dialog In Favor Of Dissertation which offers a better fit to this medium. I've been overruled. I will continue to make small edits to pages for the sake of brevity. -- Ward Cunningham
I recently stumbled across this early description of the c2.com server with hit statistics for the first three years of operation.
Discussion
2000 wiki itself
The Wiki Mind Wipe, followed by the careful deletions of the "Wiki Reductionists" for one morning in Europe (the time lag with the West Coast being very relevant to the ensuing hyper-muddle), created significant controversy which divided several veteran wiki authors; the disputes have not been fully resolved, but have led to a widespread disgust of Wiki On Wiki topics.
As someone who willingly identified with the Wiki Reductionists and indeed coined the phrase, although I made no deletions on the day itself, I would strongly argue that the controversy, the division, and the disgust were caused mainly by following what Karl Popper would call Enemies Of Wiki Open Society, people operating through a combination of Unethical Editing, anonymity and Pseudonymity With Untraceability. As far as the enemies were concerned these effects were quite deliberate. Especially the division. -- Richard Drake
Sam's posts on Microsoft technology revealed a depth of knowledge on the topic. But the responses by others revealed a pervasive Anti Microsoft Bias On Wiki of some of the most active posters at the time. Over the course of two days (if I remember correctly), he followed the reverse link from his Home Page and deleted all signed content he had ever contributed to this Wiki. This upset a number of people. (...to say the least! ;-) The following Saturday, I spent pretty much the whole day doing Wiki Mind Wipe Repair: On every page he had changed, I fixed the text so that the surrounding discussion would still make sense. On some pages, I agreed with his previous comments so strongly that I put my own comments in their place, in my own words, signed with my name, making it look like people were arguing with me, rather than Sam. And I restored most of the objective technical content through, sans his signature, because he had made some really valuable contributions to the factual content of this site. -- Jeff Grigg
Page Hits
In 1995, I started keeping wiki pages in a directory that let them show up in the disk-usage (du) statistics that I collected about once a year. This table shows when I made the record and the number of 1k blocks consumed by wiki pages on that date.
Nov 29 1994:
-
Dec 15 1995:
2426
Dec 1 1996:
5134
Dec 31 1997:
10600
Mar 25 1998:
14554
Dec 2 2000:
62919
I have compressed logs around somewhere but can't put my fingers on them. I have located some early mail that indicates wiki went public in 3/95.
Here is a graph I made when I still counted page hits.
c2.com
1998: Extreme Programming
Proponents of Extreme Programming showed up on the Portland Pattern Repository site and started talking about Extreme Programming, what it is, and how to do it. XP advocates seemed to be talking about XP at every possible opportunity and seemingly on every page with content the least bit related to software development. This annoyed a number people who were here to discuss patterns, leading to the tag Xp Free Zone, as a request not to talk about Extreme Programming on that page.
It was difficult to pick out the Design Patterns discussion on Recent Changes, because most of the activity was related to Extreme Programming. Eventually, most of the Design Patterns people left, to discuss patterns in a "quieter" environment, and people started referring to this site as Wards Wiki instead of the Portland Pattern Repository.
This was also the start of a discussion (argument? ;-) between Ron Jeffries and myself that lasted several years, and eventually convinced me to try Extreme Programming practices, and eventually grow to support the whole goofy idea. ;->
-- Jeff Grigg
1999: Change Summary (discontinued, but led to Quick Changes)
What's a Recent Changes Junkie to do? There are many changes, so it's hard to tell which ones are "worth reading". Was a change just a minor adjustment of spelling, punctuation, or correction of web links? Or was it the addition of some interesting new content?
Some good souls started taking Recent Changes, annotating each line with a brief description of what had changed on the page, and posting this to the Change Summary page. Good idea, but remarkably time-consuming. It didn't take long for this practice to peter out, because it was simply too much work. This Wiki added the "Minor Edit/Recent Edits" feature to reduce the Recent Changes clutter. Other Wiki sites have a feature where the poster, can enter a line of descriptive text when saving changes to a page, which puts "Change Summary" data right on their "Recent Changes" pages.
-- Jeff Grigg
("Minor Edit/Recent Edits" feature removed in October of 2004, due to edit wars and spamming issues. See Minor Edits Disabled Discussion.)
2004-2005: Thread Drift
Proponents of Chatter For The Sake Of Chatter showed up on Wards Wiki and started talking about themselves, what wiki is, and commenting on every page in order to leave their signature. These newcomers got in lots of verbose arguments and Edit Wars with the regulars, and with each other. This annoyed a number programmers and XP advocates who were here to discuss programming.
It was difficult to pick out the Programming and XP discussion on Recent Changes, because most of the activity was related to Chatter For The Sake Of Chatter. Eventually, most of the programmers left, to discuss programming in a "quieter" environment.
To set the record straight: major XP advocates drifted away long before the 2004-2005 season. And the kind of problems that happened in 2004-2005 have been with wiki before, arguably at a lower intensity but with similar effects. Wiki seems to repeat its history.
(See: Missing Wiki Before Xp.)
Related:
Please Please Dont Categorize Every Page On Wiki - history of categories in Wiki
Wiki Dark Ages
Out of curiosity, I tried the Wiki Archive to check revisions of common C2 pages (e.g., Front Page), and found in most instances there are no history files between 1997 and 2001. But I did find Kent Beck had a revision in 2000.
Was the site name changed in those years? And what is the name if it was located on different server? -- dl
The wiki script has several aliases (the cgi-bin form was mandatory for several years, the www has always been optional.):
c2.com -- preferred
Do we know what the first ever wiki page was? Is there any way to tell at this point? Does it still exist?
The original script retrieved Front Page by default (same as it currently retrieves Welcome Visitors). Likely Front Page was the first wiki page. I don't know how I could tell for sure without finding those old logs. -- Ward Cunningham
Some of the most popular websites and open source projects use the wiki system.
Yes, some of the biggest and most important sites and open source project do use wiki. Such websites are:
Although billed here as an important site, it seems to be now part of Wiki History - see en.wikipedia.org
What Wiki does is to open the Web to those who might not contribute elsewhere. Everyone knows that control / editing is often minimal or non-existent, so hopefully it will engender a more critical faculty in web users who, especially the less sophisticated or less skeptical, often seem to accept all that they read online as being true in all aspects. Vive le cynisme; vive le Wiki. -- David M
When did wikis introduce the true groups function and start tracking the movement of a user through different articles (keep knowledge of the user inserting/editing)?
A present part of Wiki History is that Recent Visitors has become difficult to maintain as it keeps getting deleted. Here is a Copy Of Recent Visitors to help keep it available. The version history is such a mess it is difficult to see whether it is the correct version. This is (or was when I created it) version 10253 from the archive. -- John Fletcher
So Grammar Vandal has had one of his delete-trantrums again... I don't know why he/she/it bothers. *sigh*
Is there any more recent data of innovations or the number of users?
Review of 2013
I do not know of anyone keeping track of visitors. I have been maintaining the pages of Changes In Month for a number of years now and always record the number of pages at the end of each month. I keep a note of the numbers on a spreadsheet. I have done some calculations on that and it gives a growth in pages running at a current annual rate of about 600, or about 1.7% (end of 2013). Some of that is the admin pages I create to monitor each month, say about 25 per year in total. The trend of this is upward from a low point of about half those figures at the end of 2011. In terms of what is actually going on, there are a small number of active discussions which can be located either from Recent Changes or by looking on Implicit Topics and going to one of the month pages, which will give a list of the topics active in that month. -- John Fletcher
Review of 2014
In the course of 2014 I have ceased to create the Implicit Topics pages as there was no use of them being made. I forgot to make the new ones and no-one noticed as far as I am aware. There has been an increased level of activity towards the end of 2014, as well as the Bot War which did not result in an increase in the number of pages by much at all. -- John Fletcher
See original on c2.com