Emailed Account Information
Another big security failing I get all the time is account information being sent to me which is obviously for another person - somebody entering there email address wrong when they sign up for a service.
Recently had O2, Vodafone, Charter etc. all send me logins, passwords, bank account information - you name it all because there sign up process doesn't first verify the email address.
I hate to break it to them but entering your email twice is not the same as verifying it.