It's basically just a service to bring people together, with the same interest... a glorified online database.
Get someone to list a couple of countries and cities and provide a
function for them to list their details, or a chat area for them to arrange a meeting. Do not make it Bitcoin specific..
...Build a drop down menu, for different hobbies.. if it's coin
collection, people can select that and only coin collectors will be show.... if they select Bitcoin... only Bitcoin traders will be shown. If you open it up, you could get away with it.