Re:How does the Gmail unsubscribe button work?
by boomlinde on Saturday May 30, 2020 @12:07PM
(#23362079)
RFC2369 from 1998 is "very new"? Funny. I guess it's either a matter of perspective.
Adoption of it doesn't matter insofar that you can use the same link in the body as a fallback, which was part of my suggestion.
"ESPs" don't care because cumbersome and convoluted multi-step unsubscribe is a selling point for the majority of people who use such systems. They have moved from simple mail based unsubscribe which was the norm for years.
Because List-Unsubscribe is very new and not supported by all email clients or ISPs (inbox service providers). Since adoption is so spotty, most ESPs (email service providers) start from a baseline of a web unsubscribe system and (maybe) supplement that with List-Unsubscribe as well.
This situation will likely improve over time.