[ghaff]

A huge amount of not-really-spam goes to my Gmail spam folder. It's mostly email I at least implicitly agreed to receive by dint of attending a webinar, downloading a report, getting scanned at a conference, or even explicitly signing for a newsletter at some point.

I know some people would rather none of this email existed, but it does and it's how, in the real world, it's part of how customers are acquired and kept. The legit mail of this type all has obvious unsubscribe links but I'm sure a lot of people just flag it as spam instead and, over some threshold, it starts to go to others' spam folders too.