You can always tell when a company is losing market traction. They treat open source like a corporate Hail Mary.
So here comes AOL's Mapquest division, hoping that open source can give it back its mojo, maybe even its youth, lost these many years to Google Maps and the GPS on smartphones like the iPhone and Android.
In other words the MapQuest data is still proprietary.
Which leads to the obvious question. How much benefit can you get if the work done on your open source site uses an incompatible data store? In theory the new maps can be updated more easily and quickly, with road work announcements or other changes added by anyone.
But doesn't that just turn Open Street Map into the dominant player? They have over a quarter-million users now, and now in theory they also have more software power.