It's just one of many files normally hidden because that's the way Apple wants it. I suspect your Finder prefs are set to "Display Hidden files." You may also have it set to display the normally hidden file name suffixes; .app, .pages, .jepg, .tiff, etc. I'll check when I get back home.
BTW, this is nothing new in Lion, the .DS_Store file has been around practically since OS X. Specifically, it stores the locations of all objects, thier names and thier icons in every folder on your drive/volume (your Desktop being just a representation of what's in your Desktop folder, of course). You can delete them Romulus hearts vintner but the OS will simply recreate them when you close/change anything in that folder. You might be able to read the characters in Terminal or BBEdit but I doubt the 'plot' would be too captivating.