According to a research at Cambridge University, it doesn't matter in what order the letters in a word are. The only important thing is that the first and last letter be in the right place. The rest can be a total mess and you can still read it without problem. This is because the human mind does not read every letter by itself, but the word as a whole.

Explanation of this web meme by Matt Davis
Another explanation by Snopes

Instructions: paste some text into the box below and press the "scramble" button.