I like this idea alot, maybe something like this:

User opens app, makes a possible meetup that s/he is into , it then shows up on the map as just the title of the Group, along with maybe an interest count of initially 0.

If others click on it enough, the original users gets notified that this 'has momentum' and whether or not they want to schedule an actual get together. If they do, all other people are notified of the event.

like meetup.com, but the emphasis is on the location.

Is that what you were thinking ?