The new fun comes in the form of an executable attached to the message that, if launched, infects your computer with a virus that can potentially waste your hard drive after Jan. 1, 2000. Thus the affected user will assume they've been bit by some Y2K bug.
Here's a nice little bonus: the virus will also change your homepage to a specific one on GeoCities, which apparently contains a banner for an adult site. The site had logged over 2,000 hits between Thursday night and Friday morning; it's unclear if it was the virus at work, or curious people wanting to see the web page contained in the virus.
I've seen lots of gimmicks to draw people into your site and generate ad revenue, but I think writing a virus to take them there pretty much takes the cake in terms of both originality and stupidity. "How'd you find me? Oh yeah, the web page..."