The following is an explanation of what my tags mean. In six months when I can't remember what things like "WayBack" mean hopefully I'll remember that I wrote it all down.
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2007-08, 2007-09, etc - These are the year-month I bought the game.
2-player, 3-player, 4-player, etc - It supports this number of players.
age-of-sail - Naval combat with sailing ships
air-combat - combat, in the air, probably with planes
ameritrash - Ameritrash related
back-stabber - Back stabbing is considered a normal part of game play.
bgg-reference - Linked item has info about BGG.
books - Some related to books
buy_this - I want to buy this.
campaign - The game can be played as a campaign where units would be sustained and improve/degrade over multiple scenarios.
complex - Rules are complex and not for the faint-of-heart.
dcorbin - David Corbin owns this. He doesn't populate his owned games so this lets me look for things I might like on game night.
DragonCon07 - Something I bought at DragonCon 07
expansion - It's an expansion and not a standalone game.
FFG - Bought from Fantasy Flight Games
filler - Light, quick game suitable for play between main events
game_night - Article relating to game nights
gateway - A gateway game.
geekgold - No idea, apparently something to do with GeekGold
geekmod - No idea, apparently something to do with GeekMod
intro - No idea
len:XX - Can be played in X minutes (15,30,60,90,120,240,360,360+)
local - Something that's local to me (north of Atlanta, GA, USA)
long - It takes a long time (over two hours) to play
multi-player - Supports bascially any number of players, generally something where you can sub-divide forces to include more people.
naval - I think this means there's water involved.
negotiation - You might have to talk to someone to get what you need.
new_users - I think this is related to new users on BGG.
Nostalgia - Something I played in my mis-spent youth (around 1978-1984)
owned - I own it. (deprecated)
print&play - It's a print-and-play game.
quick - Takes under 30 minutes and it probably fast-paced.
racing - It's about racing.
rating(s) - Has something to do with rating, probably on BGG
real-time - Game is played in real-time, i.e. with simultaneous action
recommended - Game was recommend by BGG Personal Recommendations
sci-fi - A sci-fi related game
short - It's a short game, probably under an hour.
simple - Nice easy game for beginners
solitaire - You can play by yourself
space_combat - Game involves spaceships fighting other spaceships
star_trek - Star Trek theme
T&T - Bought from Toad and Troll
tactical - It's a tactical level game
Tanga - Bought from Tanga
tickler - Something I'm interested in and want to check out later
tile - Probably a tile laying game
tips - Tips about something
trading - You have to trade with other players
tutorial - It's a tutorial
very_long - Takes 4+ hours to play
vikings - Viking theme
wargame - It's a game, about war
warroom - I bought it at the War Room in Duluth, GA
warroom_stock - I saw it on a shelf at the War Room in Duluth, GA in Sept/Aug of 2007
WayBack - Games I've owned since well before Aug 2007 (when I started gaming again)
werewolf - Related to the game Werewolf
zombies - Zombie theme
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Old game length tags:
quick - Takes under 30 minutes and it probably fast-paced.
short - It's a short game, probably under an hour.
long - It takes a long time (over two hours) to play
very_long - Takes 4+ hours to play