Perhaps DNL felt the need to spam the Metafilter front page after being rejected as a cast member from Saturday Night Live. Perhaps DNL are just his initials. The history of events leading up to his crime is unclear. What is clear, however, is that his self-link occured after 5 posts to Metafilter (and one to Ask Metafilter). Here are all six in their full, ahem, 'glory'.
"Bob Barker?Really?I hope that guy won a car. Or at least played Pinko."
(from the Tattoo Safari : Idolatry or Irony? FPP)
"For some reason, all I can think is "Homer Simpson" and "d'oh"."
(from the Beer! Now! Fire! FPP)
"I ordered my own business cards, and got the address wrong. Instead of saying Y Nth Street, I did N Yth Street. :("
(from the Did you mean charwoman? FPP)
"hal9k -- :(Cost me $18, too."
(also from the Did you mean charwoman? FPP)
"Al Gore just hasn't been to Africa for long enough, I guess.(sorry, all the good jokes were taken.)"
(from the Afrigator. FPP)
"Probably not what you're looking for, but a few years ago, Readers' Digest ran a quip about a guy who wrote an essay about ERA, universal sufferage, and the women's rights movement. Unfortunately, the "R" key is next to the "T", and it came out titled "Movers and Shakers in Women's Tights"."
(from the Most famous typo question on AskMetafilter).
DNL went to more effort than most spammers. He hung around for almost a year and 'contributed' more to the site than most spammers normally do. But in the end he rather blatantly self-linked, an action someone who had planned on contributing to the site in any meaningful fashion should probably have been aware of. His account disabled by mathowie himself, he may return one day, but legends of his ghost haunting the site continue to this day...