I feel like facebook rather than stay stagnant has actually declined. By trying to be everything for everyone, it is a diluted, unorganized, mish mash of things and it's hard for me to even grasp what the core value is anymore. Is it a social network? a photo app? a news aggregator? a gaming platform? one thing is for sure by spreading out to multiple audiences it opens them up to be competed with. At least twitter has stayed true to it's original intent.