Market Place:
WTT = Willing To Trade
OBO = Or Best Offer
Satoshi = 0.00000001 BTC  (Currently the smallest BTC that can be sent. Also the creator of Bitcoin)
PP = PayPal
USD = U.S. Dollar
EUR = Euro
GBP = Pound Sterling
CAD = Canadian Dollar
AUD = Australian Dollar

Hardware:
ASIC = Application-Specific Integrated Circuit
FPGA = Field-Programmable Gate Array
GPU = Graphics Processing Unit
BFL = Butterfly Labs
Hash = Computation unit used to label the speed of mining hardware. [citation needed]
Kh/s = Kilohash per second. 1,000 h/s
Mh/s = Megahash per second. 1,000 Kh/s (1,000,000 h/s)
Gh/s = Gigahash per second. 1,000 Mh/s (1,000,000,000 h/s)
Th/s = Terahash per seond. 1,000 Gh/s (1,000,000,000,000 h/s)

Miscellaneous:
I think Goxed is spelled "Goxxed". Maybe someone can correct me, or verify this. Pretty sure it's "Goxxed" though.
OP = Original Poster, Over Power, Faggot

EDIT: Added miner hash speeds