You can turn off these emails though, surely? At least, you can with linkedin, as I have. I am not a quora user, so I can't talk there.
That said, I usually go with the email-alias trick. Not all websites like emails with a + in their name, so I have a postmap file on my server to map service@domain to my real address. If I want rid of that sites email because they won't respect my unsubscribes, I just remove that alias.
I've also heard of people using the likes of maildrop to /dev/null email they don't want. I have maildrop set up, but no rules in force to delete stuff, just to move.
Holy shit, I thought you were kidding. I am glad you included the screenshot!
For lack of better words, Quora has always struck me as expertsexchange 2.0. There is nothing wrong with being the reincarnate-2.0.-site, but Quora seems to be resurrecting demons and zombies and death we'd rather stay in the ground.
(For comparison, I consider Reddit, with its thousands of subreddits to be a form of usenet 2.0)
Just to hold off on the Quora bashing for a few seconds - I've used Quora since 2011, and they actually have not ever added a new email item defaulting to on (for me at least, maybe I'm in some grandfathered category.)
They've done heaps of annoying shit, but that in particular is one of the few things they haven't done.
That said, I usually go with the email-alias trick. Not all websites like emails with a + in their name, so I have a postmap file on my server to map service@domain to my real address. If I want rid of that sites email because they won't respect my unsubscribes, I just remove that alias.
I've also heard of people using the likes of maildrop to /dev/null email they don't want. I have maildrop set up, but no rules in force to delete stuff, just to move.