In the few months that I have been on WordPress, I have seen a steady increase in referrer spamw. Today, e.g., I have no less than six entries from digg.com/[sitename] alone (and the day is not over yet).
The trick here seems to be to arouse the curiosity of the owner of a blog so that he clicks on the link in his statistics view—with an unintended (from his POV) “digging” of the link as a consequence.
With a bit of luck, WordPress will install some type of central filter to block this kind of spam from the statistics (which can be distorted in a non-trivial manner). Until then, I strongly advice my fellow bloggers to under no circumstances reward the spammers by following links to digg.com—nor any other link with a suspect name (e.g. “onlines-accounting-degree-info[…]”).