It's sometimes grey. One example I can give is Expedia, which provides me with a monthly 'Your [Month] Statement is Ready'-type of thing, even though I've maybe used the service once in my life to buy airplane tickets. You can't unsubscribe since it's not 'marketing' and e-mailing support didn't help either. Yet, it's marketing, because they offer promotional links ("earn free yadda yadda") and has Citi advertising below it.

Another one is 'Oh, wow, you've been getting some profile views!' that LinkedIn and other like to do. That's indirect promotion of their services. Couched as a reminder.

Today, after not logging into Facebook for a while, received an e-mail that someone commented on their profiles. Another of the same.

It can be argued that these is all a form of promotion, but this would take a less-business-friendly political climate to accomplish, if you ask me.

LinkedIn has been one of the most infuriating CAN-SPAM violators for years. So many startups do too. "Growth hacking" is probably a net negative to society based on all the spam it produces.

Facebook themselves require you to log in to unsubscribe from emails. If you've disabled or deleted your account, you still get spammed daily, and there's quite literally zero way to unsubscribe.

If you’re on Gmail, you should mark it as spam, that’s what it is. You’ll also end up blocking that address.

If you run your own email server, black hole the Facebook.com domain.

I think most of Facebook's email comes from facebookmail.com.

"if people start to complain about it, we'll just say we didn't know and that we're sorry"

-- my former boss

CAN-SPAM only applies to promotional/marketing emails.