Wiki maps

https://www.wikimapia.org

A collaboration project between Google and Wikipedia.
Google Maps is used, visitors can add information about objects. If the building is not marked with a rectangle, press the button for adding an object.

Predict that this site in the next five years will become one of the most popular sites of the entire Internet. The basis of this is the popularity of the Google Maps and Wikipedia sites.
The potential of the popularity of these two services is huge, just not everyone realizes it yet.