...because I took that for granted. Looks pretty much like all the other 'Net-speak (ITYM.., HAND, YHBT, ROFL, etc, etc), so I de-ciphered it (the "It just *has* to mean..." way) on my own, the first time I noticed it.

(Of course, it *could* have been something else entirely -- perhaps some weird British Imperial unit of heat energy, a cousin of the BTU... :-)