Question acronyms-good-or-bad mentioned a glossary of game and site related terms. So here is the start. Maybe this can be made CW so anybody can add to it. In the mean time, feel free to add an addition as answer and I will edit them into it.
- BCG, Board and Card Games site
- BCG.SE, Board and Card Games site at StackExchange
- Beer and Pretzels, a category of games that are generally considered to be light fillers. Beer and Pretzel games Source
- BGA, Board game Arena, biggest online board game site
- BGG, Board Game Geek, a site loaded with game information
- BSG, Battlestar Galactica
- CW, Community Wiki