For websites, in theory, you could have saved that email you get when you sign up for a new service (message boards, mailing lists, youtube/myspace/whathaveyou), the one that says "keep this email for your records", and probably contained some default password that you had to change?
A professional company (and free/oss software that generates these types of emails) probably includes a way to change that info with a link in that email (or a form on their site).
My hotmail account pretty much only contains those types of emails at this point in time, as that is why I created it. Yes, it would time consuming to switch, but hey, it's your choice in the end.
The unfacts, did we have them, are too imprecisely few to warrant our certitude.