The site was started in 1998, and although not many are left, a lot of the guys you talk to on here were here for the original site, when it used a free host and an ad driven forum system.
Very recently, the site moved servers and when it happened, it got ported to a new system. That new system uses a proper time format(unix) that looks like this: "983620800" whereas the old system had the date format of "March 3, 2001". Since there's no easy way of getting a text date converted to unix time format, the user date got wiped and inherited the date that the new system was installed.
Therre's no easy way to get the user dates back, and to be honest 100's of members in the database no longer visit, so the best way to probably fix this is to change the user dates on a "request basis", which will be taken care of when the site's running a little more smoothly.
This is oh so much more than you wanted to know, isn't it?