Automakers are increasingly using social networking sites like Facebook, MySpace, and YouTube to market their vehicles. They post videos, games and other content tailored for these sites' subscribers to help promote their brands and reach owners and enthusiasts in novel ways. While automakers won't disclose their spending, experts say these sites can guide large numbers of potential customers to company websites. However, some note that social media may not directly lead to vehicle purchases and that companies have little control over other content on the sites. Most agree these sites effectively extend word-of-mouth advertising online.