Thats awfully foul and anyone trying it would deserve what they get, my vote is myth though, whats wrong with people these days

We've been discussing this over at the Lycaeum too. It is, indeed, a UL tale, and a pile of BS for sure. However, about half of the media mogul fear-mongers seem to have jumped on this. Thus, just proving how stupid they really are.

Well... I did read once that the bad smell of poop was partly due to indole alkaloids.

Yes, but the UL does not concern smoking the dried shit, but rather huffing the vapors. Indoles do not readily vaporize off at room temperature. The UL may well be based upon stories about poor African kids huffing sewage, but but the idea of it being popular among kids in the USA in utter nonsense.

Someone somewhere suggested that the intoxicating effect could be the result of industrial waste being dumped into the "municipal sewage system" (or whatever they have there).

There was actually a shit sniffing episode on X Files waay back