StarCraft has a well established community that has developed since the late 1990's. Like any cultural subset it has its own jargon, taboos, member expectations and etiquette. For the benefit of new players I thought I'd gather a comprehensive list of the above mentioned peculiarities of this community to help new players make a smooth transition into the fold.
Section A) TERMINOLOGY
In this section I will define terms used in e-sports shout or broad casts and posted with regularity on Starcraft forums.
All-in: A strategy that if unsuccessful will be difficult or impossible for the aggressor to recover from.
A-move: Using the hot key "A" for attack to command unit/units to move to a location and attack any enemy forces or structures encountered on the way. Often used to denote the person in question needed no skill in a particular situation.
BM: Short for bad mannered.
Buff: Referring to balance; to strengthen some aspect of a unit, structure or ability. Likens the change to a muscular person.
Chargelots/Speedlots: Zealots with the "Charge" ability research completed.
Cheese: A strategy that attempts to secure an early win through unconventional play. Usually also an all in. Can be considered derogatory.
Food: Generic term to refer to Terran supply, Protoss Psi or Zerg control.
Foreigner: The StarCraft e-sports scene began in Korea and was the main geographic area where tournaments took place. Because of this any non-Korean player was, at that point in time, accurately referred to as a foreigner. Even though the StarCraft e-sports scene has taken hold in many other regions the term foreigner still refers to non-Koreans playing StarCraft professionally.
GG: Short for good game.
GL: Short for good luck
GM: Short for Grand Masters league.
Gosu: Korean term for a highly skilled person.
HF: Short for have fun.
Imba: Short for imbalanced. This can refer to either something that is favorable or unfavorable.
l2p: Short form of Learn to play. Generally considered rude.
Macro: Refers to management of structures and resources I.E. the big picture of gameplay.
Micro: Revers to fine control of units I.E. the small scale portion of gameplay.
Nerf: Referring to balance; to weaken some aspect of a unit, structure or ability. Likens the change to nerf toys.
OP: Short for over powered.
PP: Short for pause please.
Smurf: A player who deliberately keeps their match making rank low to play games against players of a lower skill level than themselves.
Speedlings: Zerglings with the "Metabolic boost" research completed.
UP: Short for under powered.
WP: Short for well played.
Section B) ETIQUETTE
In this section I'll explain common displays of manners, good sportsmanship and faux pas.
Match beginning "handshake"
Since timing is important and so is good sportsmanship StarCraft players often briefly offer each other an acknowledgement in the form of "HF GL", "GG GL" or some other short gesture of respect. Not doing this is not considered a huge slight, but it does bother some players.
Match over acknowledgement
When it has become clear to one player that the match is lost it is customary to offer your opponent acknowledgement of your defeat gracefully by typing "GG" or "WP". It's also considered polite to respond in kind as the gracious victor. It is however considered VERY impolite by some players to presumptively declare yourself the victor by typing "GG" before your apparently defeated opponent has done so. It is also considered impolite to drag an obvious loss out by forcing the victor to destroy all structures to secure victory.
It's my sincere hope that this topic can help any new players understand what they're reading and experiencing more clearly. If you have any questions don't hesitate to ask here or in game by messaging me.
Undoubtedly I've missed some nuances of our culture so please feel free to post any additions or revisions I need to make and I will edit the post ASAP.