Now, Google Map Maker is not new, it’s been open for quite a while to many parts of the world, just not Canada. When I first heard about it, I assumed it’s purpose weas for parts of the world where there was little or no street map information. Clearly Google has learned from the example of OSM that the interested members of the public will do a lot of work for free.
They do have an interesting model however; each edit must be approved. I made a few edits today, and I can already see that you have a map profile, and users can tell how many of your edits have been approved. The approval method is also interesting — other users can approve or disapprove your edit. The final say probably comes either from some algorithm that decides whether an edit is contentious, or that the public has a consensus on.
There are still some major differences however.
In OSM I can add a gate to a road so users can tell that they can’t drive on it. Roads can also be tagged as private. In general the data model for OSM is more able to describe features with higher detail than the simplified Google model.
Also, OSM data is downloadable in many different formats, so it can be used in a GIS or in other mapping packages, while Google’s cannot. In this respect, OSM is more open, while Google probably can’t give away the data it’s either bought or licensed. OSM is still “open”
I don’t think Google will take the place of OSM, but having more detail on those maps helps everyone.