Yes, exactly. I have the same problem with my Gmail account. Over the years many hundreds of people have mistaken it for their email address, distributed it far and wide, and entered it into all sorts of things. Sometimes I just let it go, especially if a site only sends one "thanks for registering" email. I hit delete and move on. But if the service is a particularly spammy one, I'll use the "forgot password" link, login, change the password, turn off all email-related options, etc.
I used to look for an option to delete the account entirely, but that invariably led to the same people signing back up for the same services again. Occasionally I'll try to do the other guy a favor and tell the sender that they have the wrong address. It usually isn't worth the effort. Someone has a Royal Bank of Scotland account registered to my email and no amount of emailing, filling out their contact form, or tweeting at them ever did any good so I just filtered that domain out.
Not much you can do about people sending random unsolicited communications, though. I've received some really interesting misdirected mail over the years, including some stuff from the European Space Agency, and being cc'd on an NFL player's contract negotiations with a new team.