Why do some people sign messages, "Best,"?

I have noticed several e-mails recently where the signature line was "Best," followed by the senders name. At first I thought the sender was just being funny or perhaps a little arrogant, but recently I have been seeing quite a few messages signed this way. Most of the messages signed thus were from people in the northeastern US. Is this a northeastern thing? What does it mean? Is it short for "best wishes" or "best of luck" or "I am the best" or ??? I thought the signature referenced the state of the writer or writing (i.e. "Sincerely," "Respectfully," "With love," etc.) Is there a specific etiquette for message signatures? What does "Best," mean?