iHitch is to hitchhiking that CouchSurfing is to hotels. iHitch is just an idea, but key technologies (GPS phones, GPS in cars, Web2.0) are coming available in critical mass that could transform 'hitchhiking' into a mainstream, safe, reliable and cheap form of transportation. Some metro area carpool websites have already successfully started down this road.
In a few areas, like Washington, D.C. and the East Bay, lone motorists can pick up anonymous "slugs" to take advantage of carpool lanes. Ettiquete and rules have evolved to keep the peace between you and your anonymous carpooler.