How can i use my xbox 360 controller to save things on or transport my xbox gamer profile?

i heard that someone when they played someone else just took there controller and it had all of there info on it.How can i use my xbox 360 controller to save things on or transport my xbox gamer profile?The Xbox system had a memory card that plugged into the controller, but the Xbox 360 doesn't. The controller doesn't have any memory storage ability, and it doesn't have any places to insert memory. If you want to move things, you can plug a flash drive or memory card into your system (memory card won't work on the two newest models of the Xbox 360).How can i use my xbox 360 controller to save things on or transport my xbox gamer profile?Its something you insert into your controller like a memory card that stores all your stuff. I dont think it was microsoft who sold it and I dont think they are sold in stores anymore? Maybe on amazon. I also don't think it will work if you're on xbox live because microsoft were being stupid about it since they weren't getting any money off it.