Everything in your signature, including spoiler tags, is part of the 275 px limit. Your sig was clearly over. We do allow a little leeway but yours was a bit too large. If you see others with large signatures, report them and we'll take a look.
PSV 's: Madden 13 -l- Lego: Batman 2 -|- Motorstorm RC -|- Sound Shapes -|- Sly Cooper: Thieves in Time
PS3 latest : Sly Cooper: Thieves in Time ~ Trophy Info ~ Boosting: Battlefield: Bad Company -|- Family Feud Decades