Anyone know of a good Hitchhiking app?

In the 1960s/1970s people could hitchhike across the nation without too much trouble. These days that's pretty much impossible, and not due to crime, but paranoia and distrust. (Which is ironic considering we're so much more "connected" today).

Anyone know of a decent app or service where you can have a "hitcher's profile" so people can see where you are, where you're going, ratings from "ride givers" and the like?

I'm going walkabout soon and would love to match a couch surfer profile with a hitchhiker app to travel the country/globe if possible.

Any ideas?