I registered a few years ago in the all cool and trendy teenager cellphone social networking page uboot. At first it was really nice because I could send text messages for free but after some time they couldn't afford that anymore.
I haven't used that account since but I still get spam (or 'business'...) emails from other companies in the name of uboot. At the end is always that nice message that says 'login to say NO to our emails'. Well... I tried, and after finding out my username from archived emails and trying to recover my password I find out that my account doesn't exist anymore. Now I am still on their mail list from which I can't unsubscribe because my account got deleted. Really annoying.
I really think that online businesses maybe have to send emails like that to survive, but I really never got asked to get these emails and unsubscribing shouldn't be more complicated than clicking on one link.