That has nothing to do with Firefox, which doesn't even do email.

If you are using Firefox to access your mail, you are using "web-mail". You need to seek support from your service provider or a forum for that service.

If your problem is with Mozilla Thunderbird, see this forum for support. http://www.mozillamessaging.com/en-US/support/
or this one
http://forums.mozillazine.org/viewforum.php?f=39

Its not Firefox problem, its your Email program. Maybe you visited, searched or subscribed to very few of those sites and that's the reason that they keep spamming you on your email id. However you should check this:

Parental Controls

http://kb.mozillazine.org/Parental_controls

Check and tell if its working.

And you shouldn't put your email address on public forums like this one.

Most email services have a "Black List" or a "Block Sender" feature. It may take a lot of work, but eventually you can get free of them. But whatever you do, DON'T click on "Unsubscribe" on ANY of these emails. Doing so only confirms that your address is valid and you will get even more trash! Good luck! <ckd>