I much prefer contributing my work to OSM because it's run for free for people like me whereas Google is a multibillion dollar company and shouldn't really be soliciting free handouts from skint backpackers.
But this gave me an idea. Maybe there are some websites that offer real incentives to crowdsourcing activites such as money, free stays, free gear, free tickets to participants who contribute a lot of good info or achieve set goals.
Besides contributing to mapping, other possibilities would be reviews of places to stay or eat, photos of attractions, correcting out-of-date information, etc.
Does any such incentivized crowd sourced travel themed website exist?