You know you're addicted when...
... you blow off your girlfriend
when she's in one of her special moods because there's been an update, and you
can't understand why she's upset.
... you can - and do - read Faux Pas in one sitting, despite being in the middle of your exam period - because Wendy's fics are brilliant like that. (Does that count as fbk?

)
... you can't remember your parent's first names (mum? dad? ... er?), but you can quote 'Chip Off the Old Clark', complete with accents ('Moma, why can I fly? Why can I bend steel bars over my head? Why wasn't I hurt when Uncle Luke shot me?').