I noticed them doing that as well, and did what I usually do with companies that get too chatty: First, turn off the notifications, unsubscribe, etc. Then, if they ignore my preferences or keep adding new categories of notification that are enabled by default, I add a client-side rule to throw away everything they send. This way they get to keep thinking that I receive their spam, and I don't have to see it, which is a win-win (though a sad loss for email in general as an obsessively reliable communication system).

This worked out fine for Facebook: I visit their webpage when I want to know what's going on over there, and they never send me email.

Facebook's email messages used to be pretty useful; they used to contain the actual content of posts. That means if you also turn off remote images, you can actually read Facebook posts without Facebook having realized that you've read it. I've always done this for privacy, until they stopped putting the actual post in their emails.

Yes, but it also stops sending you normal e-mail notifications, which is IMHO only annoying because I prefer to use my e-mail client to read messages, invites, etc.