No, it's not. Maybe it was when we didn't have RSS and other "push" systems like Twitter and Facebook to handle people who didn't know who wanted to see their updates but assumed somebody might. Now, however, there is little reason to push content directly to my inbox rather than letting me specify the sorts of things I want there.
I'll put my email address down on a web site if they haven't launched and I want an email notifying me of launch. I think that's a reasonable time to email me. I think it's also a great idea to offer an easy "sign up to have us email you our blog posts" for people who don't have RSS but would still like to benefit from receiving updates. People who release specifically-made-for-email newsletters are either not taking enough advantage of modern methods of online communication, or they're assholes who care more about my seeing their name than they care about whether or not I want to see their name.
I _try_ to use unique email adresses, but it's a bit of a pain so I only end up doing it when I suspect spamminess, perhaps there's an opportunity here, a simplified way to auto generate single vendor/website specific email addresses directly from mail clients. It'd be reasonably easy to do it inside gmail on chrome, but I'd wNt it to work the same from my phone, iPad, laptop, desktop, and webmail. That makes it a bit harder. Perhaps a mail server based scheme where I can bcc a specific address and have the mail server/proxy deal with everything...
No, no they don't. That was pre-facebook - most of those users have moved there now.