User-created tags on a social network

Hi, I’m working on a project to develop a social network for my town and came across OSM and think it might be useful for what I’m going for.

We are aiming to have a map of the town with toggleable overlays for different tags representing interests, hobbies, and aspects of the community. I have figured out how that works but am wondering if there is anyway to accomplish the following:

  1. Allow users to create markers (representing places or events) that post to a specific overlay
  2. Edit markers that they have created, without being able to edit markers they didn’t create
  3. Allow users to create their own overlays with privacy/sharing settings
  4. Fix the map boundaries to not scroll/zoom past a set location

Any help would be appreciated. Does this sound like a feasible idea?

Cheers!

Have a look at http://wiki.openstreetmap.org/wiki/UMap and have a deep exploring on its features.

Maybe it comes near your aim?