There are some posters who joined right at the beginning who still post.
Charliehall joined on 1/2/07, and he still posts.
Joseph (the original one) joined on 9/20/06. He still posts under many different names.
yiddishemishpacha joined on 5/2/08. He last posted a month ago.
Those are just a few names I found by looking at a very old thread.