...You start pointing at people and saying "this!" when they say something you agree with.

...You say "lol wut?" to yourself after seeing something a bit strange, somewhere.

...You look forward to ht27's daily football threads purely so you can bitch about your least favourite footballers/football clubs.

...You plan your week around the last.fm update to make sure you're first to spot it and can post the thread on the music board.

...You have a near-irrepressible urge to use "CURB YOUR FUCKING FACE" as an insult.

Any more?