When you log onto the OSM web site, you get this really nice map of all of the users hometowns, click on the bubble, you get the user name. This is a great! Disappointingly, I have discovered at least 80% of the "users" nearby are in fact people that made an account but never managed to make a single change on the map. Also, many of the accounts are several years old.
I propose that OSM should delete any account that is over a year old and does not have any actual map edits. The account is dead.
This will make the "find nearby users" feature signal to noise go way up and will keep everybody honest about the actual size of the OSM community, which is probably 20% of the registered user count.