The sending of unsolicited, anonymous messages to a mobile phone via Bluetooth. The file format is VCF, which is used for exchanging contacts. The message text is placed in the vCard header, and appears on the screen of the target device. Bluejacking emerged in 2002 and is used mainly for jokes or to say hi to someone, as well as for marketing purposes. There is an unwritten set of rules in the bluejacker community about not disrespecting the target.