I've had hitchhiking on my mind recently. The protagonist in Into the Wild, the book I just finished reading, hitched his way across the country. I talked to some guys at the last Providence Geeks meeting who built software for managing point-to-point transportation networks. Their software wasn't designed for hitchhiking, of course, but it dawned on me that ride sharing is a possible application for online social networks. I'm not all that familiar with online social networking, so it's possible that people are already using it to share rides. I don't think the technology is quite ready, since if you really wanted to approximate hitchhiking on an online social network, you'd need a critical mass of users who are accessing the network from portable, GPS-enabled devices, and I don't think that such devices are common enough these days. Even if that was a reality, I'm not sure how willing people would be to offer rides to or accept rides from virtual friends, never mind virtual friends of virtual friends.
One of the things that fascinates me about hitchhiking is how it seems to have gone from an fairly common activity to something that few people would ever consider doing almost overnight. At least, that's my impression of it. My impression is probably not entirely correct, hitchhiking probably wasn't all that popular prior to it becoming unthinkable (my best guess is that this inflection occurred between 30 and 40 years ago) and it's probably more common today than I think it is. Still, I wouldn't be surprised if a confluence of factors including, but not limited to, pervasive online social networking, rising energy prices, concerns about pollution, and traffic congestion leads to a greater number of people sharing rides in the not-too-distant future.