I joined in March 2007 and the only people still contributing since then are Madandra, John_Findlay and Birdieman.
I'm not sure if there's anyone since before then still here.
I lurked for a while late 2006 early 2007 before signing up in April 2007. Now a confession, I was on Golf Magic before that. Didn't like it there too much though. Too many silly spats at the time. On here, well, I think it was all Atticus_Finch fault as I had to post a comment on one of his posts. The rest as they say is history.