Is a file really deleted?

Well, you see, when you delete a file it isn't really gone. And there is nothing to write over all the data with a 1 or a 0 (that would take flippin’ ages), the bit that tells you where a file is located is removed and then the computer will write over the data in the future. The data is still recoverable if someone knows where and how to look for it. Unless of course you get special software that will write over your data. Or you could do it manually with a massive file that contains no useful information (say, a giant GIF of nyan cat) and fill up the hard drive with it. 

The reply I got  was: "Are you really suggesting that a giant GIF of nyan cat contains no useful information?!? I suggest you get your priorities in order!"