A recent report from forrester.com tracks social participation by car consumers.
Here are some of the highlights.
Most active on social applications:
Customers of Mazda, Honda, Pontiac, Hyundai and Jeep - between 57% and 68% active participants
Customers of Chrysler, Toyota, Dodge, Buick, Subaru and Saturn - between 53% - 63% actives
Ford, Nissan, Chevrolet, GMC and Mercury - less than 51% actives
The report also lists their level of social activities, e.g. critics, creators, joiners, collectors, spectators.