There's this myth that automated spam detection is hard because spammers are all very clever masters of disguise.

No. Spammers are stupid as a shoe. They have dog shit for brains.

Automated spam detection is hard because the line between spam and "legitimate" marketing activity is a fiction.

@danslimmon just block all legitimate marketing emails problem solved
@azonenberg @danslimmon unfortunately, there are, for example, banks who will stop sending you transaction notices if you report their spam as spam