The Markovian Parallax Denigrate is the oldest internet mystery. It came from a a proto-web chat community called USENET that was popular in early 1990s.
In the year 1996, the USENET community reported unusual spams coming from a username called Markovian Parallax Denigrate. The messages were made by random words and phrases strung together and distributed among the community.
The title of the posts started with “Markovian Parallax Denigrate.” Then followed by the words seen below:
jitterbugging McKinley Abe break Newtonian inferring caw update Cohen
air collaborate rue sportswriting rococo invocate tousle shadflower
Debby Stirling pathogenesis escritoire adventitious novo ITT most
chairperson Dwight Hertzog different pinpoint dunk McKinley pendant
firelight Uranus episodic medicine ditty craggy flogging variac
brotherhood Webb impromptu file countenance inheritance cohesion
refrigerate morphine napkin inland Janeiro nameable yearbook hark
Hundreds of these messages flooded the USENET discussion groups. At the time, the community was only filled with talented people with computers in mind. But none could figure out what the words and phrases meant, how they were generated and how they were distributed.
When USENET was eventually replaced by the World Wide Web, the mystery started to dissolve and forgotten. At Google’s public USENET archives, only one message remains with a subject line that reads "Markovian Parallax Denigrate." The name on the sender's email address was Susan Lindauer, a former journalist who was arrested in 2004 after allegedly serving as an agent of Saddam Hussein's government. Since then, she has been a purveyor of sundry conspiracy theories, from a Lockerbie bombing cover-up to 9/11.
The Markovian Parallax Denigrate was regarded as the first ever internet spam.