This technique was perfected on the forum Glocktalk in 2008 by three members, KilgoreTrout, MacG22, and TylerDurden. The orignal poster created a slow, uninvolving thread about watching a pepper rot on his windowsill. The three GT members then engaged in passionate discussion about peppers, pepper artwork, growing techniques, and etc.
The effect is often hysterical for those creating the pepperthread, but others seem to remain oblivious or feel they have simply encountered officionados on various topics.
Pepperthreads are often informed through quick but thorough research using Google.