Note to startups: make a product worth using and you won't need to spam your users' inbox. They will email you!
I don't think that sites sending emails is always spam. There are some things that I want in my inbox. I like fan page updates from facebook, my unfollows on twitter, updates on people and companies I follow on AngelList etc
Of course I do prefer opt-in and links in the emails to unsubscribe without having to log in. But email is just fine for me - gmail knows what I like.
First there's the confirmation email, then the congratulatory email for confirming.
Now if this is one of those Launchrock type fake signups, then you get reminder emails about spreading the word to skip the queues, which is probably lies anyway. But let's assume you got in.
Then the notifications start (StrangerX is now following you on YetAnotherApp). Turning off these notifications involves finding the settings page on the app, then unchecking fifteen checkboxes. At this point, I'd rather delete my account, but of course that feature's not built yet (it's an MVP duh)!
Then constant emails from the founders: "We noticed you signed up for our awesome app three minutes ago but you haven't started loving our app yet. Why not? Feel free to ask any questions if you have doubts about loving our app."
Then feature updates. And as was pointed out in a post couple of days ago, they don't even bother to remind you who the hell they are.
To top it all, a lot of startups still use DO NOT REPLY email addresses. W.T.F. Even Joel Spolsky's new Trello app did it! (Hello Joel! How about going back and reading some of those Joel on Software articles?)
Many don't have an unsubscribe link in their emails. Some do, but that takes you to "manage subscriptions". The only ones which have a proper 1-click unsubscribe link are the nice ones I don't mind hearing from.
Boy that's a long rant. I should start blogging.