It's not against YouTube's ToS to run pre-roll ads of any length, of course. But I think he was just selling get-rich-quick schemes or something. At the time YouTube ads were more rare and generally short, like 15 second TV commercials, so it was weird to see long-form content as ads. He absolutely saturated the site with this ad for a while to the point that it became a meme. I'm guessing a significant percentage of YouTube's user base at the time was served that ad at least once.

Yeah I still occasionally get really long ads that must be just to see who watches all (most?) of them.

He defrauded investers out of $120M.

I couldn't find any record of a conviction with a cursory google

https://www.sec.gov/enforcement-litigation/litigation-releas... They are not convicted yet.