I've been maintaining a list of local tech user groups
since the late 1990s. Every few months I put the URL into the WWW Link Checker
and update the page. There's a lot of turnover. If I'd been detail-focused I could have been tracking when groups came and went as a sort of graph of tech, but I didn't collect data on added and moved-to-inactive-or-dead. Anyway, I just cleaned it up again. Go play.