Is it at all in the realm of possibility that this will be a thing anytime soonish at all? I have a list of PMs that either got no response, got responses but are now dead, and/or that I just want gone. Would really like to see this implemented.
This is definitely something I've wanted to do for some time now.
I've come up with a solution for letting people delete convos (and thus leave the convo and receive no notifications for future activity in that convo), but it's a complex feature that would demand an entire weekend. I'll have to make time for it, I just don't know when that will be.
I will definitely do it before I develop any major new features but after I fix the current bugs that are impacting people today. This is definitely the most important and most requested feature on my plate. :)