I was helping Lenny look up an asian video. So I looked Video in the search and found an unusually high number of "video" results posted by PiffStenis.
So I clicked his name.
And looked up every post he created. This is the entire list. The results start and end at exactly 1 year and a day.
http://www.gfy.com/search.php?searchid=2481371
For an entire year every thread he started was is spam. I know there are a lot more like him, but I never actually looked one up before.