I have seen that several times over the past few years, and every time it gets me. It's really, really amazing! Is it really because of the first letter? Or (as I believe) is it because of the "proper" combination of letters? Edit- not the Proper combo of letters in the right sequence, only that all letters in a word are included in the word- not in the right sequence, but there (included). Hope that makes sense.
Could never figure that out!
Either way, I love it.