Sam's comments on Meetups mirror my experiences, though I'm not in a tech hub area. It depends really heavily on the person organizing and what kind of outreach they've done to people, existing groups, and organizations in the area. I've seen a few groups flare up really enthusiastically, then dwindle over a few months. I've also tried joining some existing meetups that feel most like people are sticking around more to hang out with the other people than because of value from the meetup.
Likewise for finding a technical cofounder. As a technical person I've spent some time thinking about the other direction, and (after a rough experience) there's no way I'd try to get funding with somebody I didn't know very well.