Bluetooth-based social networking software is rooted in the 'bluejacking' phenomenon. Early bluejackers learned they could find other Bluetooth devices in 'discovery' mode, sending anonymous text messages via the 'swap business card' function. It wasn't long before phone users began using this method of communication to flirt with strangers on the train or other crowded places, a practice known as 'toothing'. This has given rise to communication software that allows users to take greater advantage of their Bluetooth-enabled phones.