SpaceShare Green Travel -- carpool, community building
SpaceShare Green Travel builds ride- and room-share tools for festivals and conferences. Our sister effort Verdant Event builds complete websites for conferences with greening tools integrated.
You must create a free profile to use this site. There seems to be an abundance of commuter listings, especially for the Bay Area. There are some one-time, long distance rideshares offered and wanted, but not that many and it might be difficult to find a match. It seems they have just started offering errands, medical, shopping and airport rideshares which has yet to catch on with only 140 rides listed across the country.