Susan Mernit posits the question:
Why did they buy upcoming and not meetup?
I am sure that upcoming was a whole lot cheaper. Plus, meetup's growth is constrained by the topics they start. There are a whole lot more random (un-topicced) events out there happening than meetup can categorize. With a few more additions to upcoming.org's functionality and integration into yahoo's sites and services, meetup becomes irrelevant. The tools that meetup has built are great. But, they need to be unhinged from the "everybody meets on the same day" constraint. Central control of topics are limiting too.