So you've started to get invitations from people you know to add this Facebook application with a catchy name called Zimride. It's got the word "Carpool" attached. If you're car-free, or a car owner seeking to save some gas money, this should definitely pique your interest!
Zimride is a Facebook application that allows users to search for or offer rides, and limit the prospective responders to only those who are registered within the UCLA network. This means the people who respond to your post are affiliated somehow to UCLA as a student, staff, or faculty member. This, perhaps, might evoke some trust, some sense of community. This is, I believe, what could make Zimride different.
I think there is something intriguing about an application that might allow you to preview a potential ride match's FB profile. Maybe that person is a friend or a friend-associate of somebody else you know. (The FB profile displays friends you and that person have in common.)
Anyway, in case you haven't gotten your invitation, click on this link to add the application: http://apps.facebook.com/carpool/
You can create your profile, search for rides, or post a ride.
The profile allows you to indicate what kind of car you drive and your preferences for smoking and music.
Here's one example of a post for a ride (totally legit, by the way, since I could use a ride to the SFV for house-sitting):
On the UCLA Transportation website, you can see a table which illustrates the potential cost savings for carpoolers who share a permit to come to campus regularly. Faculty and staff who can form a three-person carpool can save between $90 to $246 per person (based on permit type). Students in a three-person carpool can save up to $90 per person. The money adds up; you're doing something good for the planet; and maybe you'll shave some time off the commute if you are able to use a carpool lane.
Good luck, everyone!