I thought this was an FAQ, but couldn't find any answer from someone at Google. The Wikipedia page on Google Map Maker states:

"The project is similar to OpenStreetMap, but unlike OSM which provides its map data under a Creative Commons license, any maps created by users of Google Map Maker are the intellectual property of Google."

OpenStreetMaps is free, more open, already in place, has extensive coverage, and lots of mechanisms to improve maps: software that parse GPS tracks and uploads the data to OSM, browser-based map editor, and even an Android GPS navigation app that maps unknown places as you drive through them (AndNav2). OSM lets us in the USA, UK, Australia and other "well-mapped commercially" countries update the map with punctual local knowledge which the big commercial guys don't bother with (new or temporarily closed roads, location of post boxes etc.).

Wikimapia is also completely open, CC-licensed, and has identified of some of the most obscure buildings you'd want.

Therefore, I have a few questions:

In the context of OSM, what is the purpose of Google Map Maker?

How is Map Maker / Map Your World better than Open Street Maps?

Why split the community between the two projects?

Licensing questions (ref.
http://www.google.com/mapmaker/mapfiles/s/terms_mapmaker.html):

Can't GMM simply slurp all the data from OSM, then build off that?

How will the GMM data be available? For example, 3rd navigation software is not allowed to use Google Maps for turn-by-turn direction (that's why AndNav2 exists - AndNav1 uses Google Maps, but could not give directions turn-by-turn).

I'm not saying GMM is a bad idea (I personally prefer the openness of OSM); competition will hopefully improve both products. It would be interesting to contrast the two system and find out the rationale for creating GMM and reasons why I'd use it over OSM.