Wikimapia

Something i really enjoy about social media is how major sites generate their own eco-structure of on-line tools extending the "mother site" and providing extra functionality especially when "mashing" it up with another data source. Wikimapia is a prime example of this and is an open collaboration tool that mixes Google Earth imagery with Wikipedia editability.

Users can mark on the map areas and places of interest and put some information about these places. Potentially very interesting, though place entries seem quite prone to vandalism (such as the Villa Park entry - though it seems cleaned up now!)