Some time ago I have installed Mac OS X 10.7 Lion on my laptop and surprisingly discover a new folder in the my directory - .MobileBackups. And its size began to grow every day.
After some googling I have found that this is a new feature of the TimeMachine.
I don’t want to use it and I want to disable this new feature. I did not found any UI handlers to do that, but I found how to disable it with Terminal:
sudo tmutil disablelocal
After a reboot, the backups should then be gone.