I suspect that these were placeholder characters left over while someone was setting up the page. However, I don't think it should have ever made it to "print".
So then, on a whim, I start searching, and find that google has 9920 hits for "asdfasdf". Simply amazing. Or sad. Or something.
One of them is a stealth asdfasdf. Note nothing unusual about the page, but check out the titlebar on your window. Sweet.
And check out the Dave Letterman Top-Ten!