I don't know if you've heard already, but I recently noticed that Google introduced its Map Maker into the US. Unfortunately, I think it's kind of a bad imitation of OSM. Though it follows much of the same concept as OSM, I noticed some shortcomings to it:
* You have to get your edits reviewed before it appears on the map. Also, if you edit a road that connects to a road that hasn't been reviewed, it won't even let you edit that road, which can be kind of annoying.
* The UI is not as user-friendly as Potlatch2. It seems to take a few extra clicks to go from just browsing/ moving around and selecting roads/ other items.
* When tested on an old computer, Map Maker was really, really slow. Potlatch 2 is way faster (though it does lag a little) than Map Maker, meaning P2 runs smoothly on a wider range of computers.
Though there are these shortcomings to Google Map Maker, there are a few things I like about it. For example, the road designations may be easier to understand by users in the US as it is actually concieved in the USA rather than Great Britain.
Also, google map maker is more well known than OSM, meaning it may attract more attention and steal the limelight from OSM. I don't want this to happen, so I want to spread awareness for OSM by maybe even placing ads on google maps. THat would be killer!