Nov 23, 2001 was the founding date of the Always Learning discussion at Yahoogroups. There were a couple of other groups involved and active in those days; one is archives only now, and one reformed with the same name but different people. Always Learning has survived for fourteen years. That's old, for an online forum! Recent posts are numbered in the 76,221 and such... and we don't have chit-chat there, so that's over 70,000 substantial posts, in fourteen years.
I missed the fifth anniversary of Just Add Light and Stir. The first post was September 2, 2010. Five years of a post nearly every day (I've missed twenty or so, I think, in scattered fashion) adds up to... over 1800, in five years.
The less placid online discussion at Facebook, Radical Unschooling Info, was five years old in February. It was created February 13, 2010.