Have you heard about the theory that the brain can make sense of a passage of text with the letters all jumbled up? This works as long as the first and last letters are in place.
At http://readingtest.sytes.org you can read the classic bit of text that describes the theory. You have probably seen it as a viral, as I think this one did the rounds a year or so ago.
Well, now some clever spark has created an engine where you can test out the theory on any site you like. Just plug the URL in the box provided and see how it works.