My coworker is a Facebook stalker

I've worked with this gal for 10 yrs. She recently joined Facebook. Every coworker I've added, she has also. Every app I play or every high score on a game I get, she has to play and get a higher score. Every post I respond to or group I join, she's there too. Our friendship has been strained lately (for other non Facebook issues at work). Then, she has to come and talk to me about Facebook every day at work. Other than deleting her, how can I handle her without coming across rude??