Just read an article in the 20 minutes paper.

Greeters are volunteers that love their city so much they volunteer to show their city to visitors. Not as a guide, but more like a newly met friend! Greeters will show special places that mean something in their lives. They would also show things visitors specifically ask for such as parks, shopping, architecture or a less wellknown neighborhood.
Greeters are no professional guides, that is why Greeters (for example) do not enter a museum with their guest(s), that is up to the professionals. 

There's a team in Zurich, so that could be interesting for the newbies or some other people who want to visit the town.

http://www.globalgreeternetwork.info/