Here's The Register's story on it.
In a nutshell: if you use the "Help Center" (just WTF is that?) you can pass it a string to delete directory contents.
If you put "hcp://system/DFS/uplddrvinfo.htm?file://c:\test\*" for a URL in IE it should erase what's under c:\test. However it looks like it only works for XP as my 2k box doesn't have the DFS directory or a uplddrvinfo.htm file.