As individual contractors, tennis players are not subject to the social media policies sports teams worldwide have used to restrict athletes' tweets. And given the sport's traveling-road-show aspect, with hours upon hours of downtime between matches, Twitter enables today's players to communicate whatever, whenever and wherever -- often without the filter of a public-relations team. The third-ranked Clijsters (left) is an avid user of social-media sites like Twitter and Facebook. Shortly after snapping this photo with Caroline Wozniacki during a changeover at an exhibition on Jan. 1 in Thailand, Clijsters uploaded it to Twitter (inset). SAMPLE TWEET "We just had a car accident on our way to the courts! So scary... Bob, my manager took the hit... http://yfrog.com/eplixnj "