I am testing uMap to see if it may work for the purpose of crowdsourcing spatial data. Please have a look and add some content:

uMap looked promising. I loved that it supported some map customization (i.e. the Stamen Toner or the OSM monochrome map theme) and that the interface for adding point, line and polygon was intuitive. I did not see any moderation tools, but was interested in the embed function... so I tried it. Not impressed. A map in a WP post, I can zoom but not add any VGI. This will not work for my purpose.

NOTE: 30 October 2015. uMap was not quickly connecting to it's servers, which was slowing down by blog load time. As such, I removed all links to uMap.