I really like the location idea, because of the potential to say "There are X other LW members within Y miles of you" or "There are Z other LW members in your metropolitan area." If you see "wow, there are 100 members in [City]? If only 10% of us show up, that's still a pretty nice group!" then you're much more likely to start / have an interest in a meetup than if you're just pinging empty space.
And, if you get people to join, seeing that number go up might be rather useful feedback.
Also, you don't even need people to manually enter their locations. IP addresses are usually enough to narrow your location down to a city or metropolitan area, and we wouldn't need much higher resolution than that.
Does anyone else think we need a better way of dealing with meet-ups? I totally understand that meeting face to face is an (at least arguably) important next-step in the rationalist-community-building project, but the fact is the front page, which was originally for all the most content-rich, accessible, and noteworthy articles is now being filled with blurbs that are irrelevant to 95% of the readership.
I can see why these posts would need to be highly visible if the meetups are going to work at all, but I think we should get the ball rolling on figuring out a better way to handle location-specific posts. For example, mandatory-but-private location setting in your profile (at least to the country, possibly to the state/province/etc for larger areas), which would subscribe you (with opt-out available) to any happenings in that area. That's just the first idea, like I said the idea is just to get the discussion going.