Last month I wrote about the Poli Car system in Italy that added an element of trust to carpooling via a text message system.

I just learned of a similar system that has been started in Seattle called Goose.

And this week’s Smart City radio program has an excellent discussion of a system in Massachusetts (which also works nationwide in theory) called GoLoco, founded by Robin Chase who previously founded the ZipCar carsharing company.

The point Chase makes on the show is that this is essentially the extension of social networking approaches to ride-sharing.

But obviously these things start slowing until they hit a critical mass, and a series of local systems will have a harder time getting to critical mass.

So here’s my question. What if we approached this confluence from the other direction? What would happen if MySpace added a transportation feature tomorrow? It might be revolutionary…