Visual Studio "Backup Files" folder in my documents

I noticed a l开发者_StackOverflowong time ago that Visual Studio creates the folder "My Documents/Visual Studio 2010/Backup Files" (2010, 2008 or 2005 as appropriate). Into that folder VS creates a new folder for each solution you open named as the solution. I think after some time without opening a solution its folder is removed. What I'd notices recently is that those folders are always empty! What are them used for?

Those are backup files. Check this link

http://msdn.microsoft.com/en-us/library/208c6tcy(v=vs.80).aspx