There's a ripe market opportunity for a free or significantly cheaper alternative to Meetup, unless I'm unaware of a competitive one that already exists. $12/month is absurd for what amounts to a BB service with a handful of social networking features.
As a user of meetup.com - not an organiser - I like the $12/month.
It keeps pretty much all of the casual spammers out. It keeps the quality of meetups high since the organisers have to put a little skin in the game - but no so much skin to prevent even small groups using the service.
I can remember when they didn't charge. The service was worse.
Actually it seems like a very reasonable price. The community (and the name) is a valuable asset. People who join Meetup discover new meetups -- it's a community with network effects. It's not that easy to reach that kind of scale. $12/month is perfectly reasonable, not because of the software, but because of the value baked into it.
LinkedIn can very easily take control of professional meetups, but no one has the brains to do it. LinkedIn has group, has events, but both features are terrible, lack good APIs and are not integrated.
I would rather join a technical group on LinkedIn with events instead of using Meetup. The community is already there and almost all of us have LinkedIn accounts.
LinkedIn: please fix groups, please fix events.
EDIT: Forgot about Google Plus and events. Another potential alternative to Meetup.
It is mostly the name that is the valuable asset. People right now think to begin their search on Meetup. Their brand is extremely valuable, but I think somebody can beat them on price and by making it easier (very inexpensive or free) to begin a new group.