Spams are repetitive messages sent in large quantity. Sporgeries are spam doubled by a forgery, [ie] with real headers (title, author, etc) but containing with random selected irrelevant or nonsense text. It is a type of attack by email to block free expression of speech by an individual poster.
"Sporgery" is a term coined by alt.religion.scientology's Tilman Hausherr "because it's both spam, and forgery." This Scientology criticism newsgroup/ usenet is one most afflicted by sporgeries.
One may argue that the sporgery wave is a form of denial-of-service, but this usually applies to systems rather than persons.
On certain usenets, saboteurs are using computer scripts to replace their posts with meaningless gibberish. A "sporge" used to be just random letters, but as the sporgers gained in skill, they replaced words in the posts with words that were the same part of speech. The result was grammatically correct nonsense, sometimes quite interesting to read.
For accessing usenet, the sporgers are using multiple throwaway accounts fraudulently opened with bogus information. The account is used until the ISP finds out about it and close it down. The sporgers then quickly hop to another ISP. They have shown a certain skill with finding ill-managed ISP's which can help them keep accounts alive longer.