This wasn't a well coded worm. It fact it was crap.

For a start they got the address wrong - windowsupdate.com isn't used by Win98, 2K, XP, or 2003. These have always linked to windowsupdate.microsoft.com, and still do so
windowsupdate.com just redirected you.

Also, it can unintentionally cause infected PCs to crash due to badly written code.

Makes you wonder what a well written worm targetting microsoft.com would do though.
Trouble is, you will always have a lot of unpatched home PCs which will host this type of worm. Food for thought for MS I suppose .. can you really protect yourself against a massive DoS attack ??