Last night I had a look at the hires Yahoo imagery here:
osm.wiki/Yahoo!_Aerial_Imagery/Coverage

Most of the places are mapped quite well, but I found that Niamey, the capital of Niger had just some major streets drawn in. After burning some midnight oil the map looks much better now, but there is still a lot to do.

Niamey has 700000 inhabitants so there are plenty of streets for everyone to map. Feel free to join me mapping the city. The more the merrier.