According to The Telegraph, the girl sent a message to her friends encouraging them to "copy [the] scenes of violence and looting that were spreading across England." Thanks to the Serious Crime Act 2007, this move left her vulnerable to criminal prosecution.
While the girl's case is one of the first to specifically cite the BlackBerry Messenger service, it is certainly not the only one. A 27-year-old man is also facing similar charges.
It's worth noting that these charges are being announced after Research In Motion, the maker of BlackBerry technology, vowed to cooperate with authorities — who blame the BlackBerry Messenger service for enabling rioters to quickly and easily organize themselves.