Assuming you mean Anand's site in general, and not just this board...
There are several members who even pre-date my crowd, which is Russ, Harvey, and LED. I know Bighammer and Red Dawn have been around a long time, I just can't remember if they date this far back or not.
To me, AnandTech time is marked by several big events. The first one which really got the members coming is the great Harvey - Tom Pabst war. That one raged for a little while, until Harvey finally just let it drop. Tom continued to take cheap shots at Harvey on his own site (much like he did with Anand, and many others he feels threatened by). I understand Tom go into it with a Quake3 developer, or something...I had long since stopped going by Tom's at that point.
The next event in AT forums history is the forming of "off-topic". Up until this point, AnandTech forums were all under a single general board. The spark which formed "Off-Topic"? - RELIGION (surprise, surprise.) And here's surprise #2 - I was outspoken, along with Harvey, *against* the religion discussions. On the other side was Netopia (Joe), and NWM (can you believe it?) back when NWM was trying to convince himself/herself to be a Jehovah's Witness. Red Dawn was in there, but I can't remember where he stood on all of it. In the end, Off-Topic was formed, and here we are.
The third big boom for AT forums was the "Hot Deals" section. This was, and is, the most dangerous forum we have...because while it attracts many great new members, it also attracts some very self-centered and difficult people who don't have much interest in our "community". Another 'believe it or not'...Hot Deals was formed over ONE SINGLE ITEM...the great Buy.com Hitachi monitor "crisis". So many people were upset about it, and so many people wanted updates and organized response, that a new forum was formed. Now it has changed quite a bit, but the origins are there. If you're new, ask someone what a "WMC (Wounded Monitor Child)" is...you'll get a kick out of it.
Well, that's AnandTech History 101. I may have stumbled on a fact or two, but that's it to the best of my knowledge. If anyone wants to add, it may be interesting.