It is a weird abbreviation, and a joke that the "South Park" creators, Trey Parker and Matt Stone, apparently had nothing to do with.
As the legend (as told by "South Park's" EIEIO J.J. Franzen in an interview on SouthParkStudios.com) goes, his brother came up with the title when he was working at a high-tech startup company.
It stands for e-mail, internet and electronic information officer. He said he came up with it just because he wanted EIEIO on his business card.
Despite its incredibly long run, premiering on Comedy Central in 1997, the often-shocking animated series has had only two EIEIOs in is 12-year run -- Franzen and Keith Nesson.
Franzen is a longtime collaborator with Parker and Stone, and also worked on two of their big-screen projects, "South Park: Bigger, Longer & Uncut" and "Team America: World Police."
He's been the EIEIO on the show since its premiere and continues to be now, with Nesson sharing the duties for a few years in the middle.