How do websites obtain your email?

[[★]Super.Starr.[☆]]

How do websites that send you junk email obtain your website?
The only places i enter it, are places i sign up for. Not myspace, or facebook with lots of ads and fake pages.
Youtube, imvu, crunchyroll, and websites for anime conventions.

[magnumgirl]

Any site that you have to sign into gets your address and passes it on to other sites. Spammers pick it up. Also if you participate in sending Forwards, those emails that have tons of email addresses on them. They circulate the world forever. Spammers harvest those also. Some sites you don't even have to sign in, your address leaves a cookie. Once your address is out there it's too late for you to stop it. Marking things as spam works but takes time to stop. You can put them on your blocked address list from the mail screen, Options, Mail Options. Click Spam, enter the address in the block, click Add Block, click Save Changes upper left.

[Lyn G]

Many sites you visit collect your information as identification, or other reasons. Most all also leave cookies on your computer. Others only use information that you choose to leave with them, as in signing up for memberships, games, newsletters, ads, catalogs, etc. Some of those sites, however, also use that information for other purposes and can share them with others. Some steal your information and can sell them to other companies and spammers. Some spammers also use automated equipment to randomly generate E-mail addresses they use to send out spam.
many other ways, too, but ... this is just one of the reasons you MUST be so careful what information you give out and to whom. If you are having a problem with too much spam, then remember NOT to open them. Opening spam alerts the sender that your address is a valid one and they send you loads and loads more. You can not completely stop all spam, but you can help to put a big dent in it.
Check mark them and click on 'Spam,' this should stop those addresses from being delivered to your inbox.
Use your spam guard and block address.
Look for the 'Options' link at upper right corner of mail screen and click on it
Options /mail options
Click on 'spam' in the list on the left.
Make sure spam guard is on, by checking in the little box.
Then in 'Blocked Email Addresses,' enter the E-mail address you wish blocked, in the box after 'Add a blocked address' and click on the 'add' button, then click on save changes at top left of screen.
You will never get mail from that address again.
This should help you to control your spam.
Other tips:
Do not ever open E-mail from people you do not know; and unless you are absolutely sure who it is from then treat them as spam.
Never, ever give out your account information or other personal information to anyone.
If you are on a site and you absolutely have to sign up for something, check the entire page to make sure you uncheck any lines wanting to send you any other info, notices, catalogs, ads, and the like.
Added detail:
Yes, spammers change one item in their addresses a lot, so you might try blocking the entire domain, by putting in
*@ thedomainyouwanttoblock.com
for instance: *@seeyou.com
Or, if they change the domain, instead of the company name you can block the name by putting in Imatheft_inc@*
Hope this helps