Founded in 2002, Meetup first gained national attention for launching Howard Dean’s brief Presidential candidacy during the 2004 elections. The site had 54,000 Meetup groups listed last May, when it began charging a small subscription fee of up to $19 monthly to sponsor the groups. Since then the number of groups has dropped to just over 10,000.
In addition to eBay, the Omidyar Network, Draper Fisher Jurvetson, Esther Dyson, Allen & Co. and Sen. Bill Bradley have collectively obtained a 10% equity interest. Given the proliferation of "social media" sites, I would expect to see a roll-up or other consolidation in the space in the not-too-distant future.
Here’s the Meetup release (scroll).