My next-cube neighbor showed me this gem yesterday (sorry no link). This guy had replied to a mailing list. His post comes with an attachment... which turns out to be a Microsoft Word document... which contains an ActiveX script... which renders his e-mail .sig!!!
And ironically, the mailing list was some kind of AIX user support forum. Wonder what percentage or the readers ever see his .sig? Didn't look like anyone bothered to flame him over it. I can't decide if the other posters are just that civilized, or it was too silly for words, or if the post never made it through their filters :-)
