Not necessarily. If you have any email address, it will probably receive spam eventually, whether you use it to enter sweepstakes or not. Here are some of the top methods that they use.
1. 'Scraping' Email Addresses from the Web
If you've left your email address in a signature, in a comment on a public forum, on a winner's list, or anywhere else that is publicly accessible, scammers can use programs to comb through the internet and harvest those email addresses.
To protect yourself, avoid leaving your full email address anywhere on the net. Don't use your email address as a username for a forum or website. If you need to share your address online, make it difficult for programs to read by disguising it so it's easy for humans to understand but difficult for computers. Ask sponsors to use only a portion of your email address on winners lists.
For more information, see Email Guide Heinz Tschabitscher's article, How to Disguise Your Email Address.
2. Sending Scams to Random Email Addresses
Sweepstakes scam emails cost nearly nothing to send. That means that criminals can afford to send blanket emails to random email addresses and hope that someone will receive them.
To do this, the scammers start with a popular email service - say Hotmail, Yahoo, or AOL - and then generate massive lists by combining common words and names. For example, the scammers might send mails to the top 100 most popular names and each birth year for people between the ages of 18 and 90. If your email address is firstname.lastname@example.org, you'll get one of these mails.
It's difficult to avoid this method of harvesting emails. The best thing to do is not to respond to these mails, so that the scammers don't get confirmation that the address is active.
3. Harvesting Data from Fake Sweepstakes Sites
Scammers like to target people who are most likely to fall for their sweepstakes scams. This means that if they can get their hands on email addresses and other personal information from people who actually enter sweepstakes, they might a bit more success with their scams. One method that they use to get this information is by setting up a fake sweepstakes site. They might even give away a small prize, but their primary goal is to harvest your personal information and use it to contact you with scams.
4. Buying Email Lists from Sweepstakes Sites
It's possible that a company could hold a legitimate sweepstake and then decide to make some extra money by selling the personal information that it collected. In that case, scammers could easily get hold of a large list of sweepstakes entrants without having to take on the time or expense of running their own sweepstakes.
5. Buying General Email Lists
While sweepstakes scammers love to get their hands on lists of people who enter sweepstakes, they will also be perfectly happy to take the chance that someone who doesn't enter sweepstakes might respond to their scam. In fact, those people might be less savvy about the warning signs of scams, making them easier targets. So scammers might buy email lists from any type of company, not just sweepstakes.
6. Hacking Into Online Databases
Some sweepstakes scammers get their email lists by hacking into online databases that have inadequate security to protect your information. This is a dangerous, expensive, and high-risk method for hackers to get email addresses compared to any of the other methods listed here, but it happens in some cases.
To protect yourself, check the privacy policies of the websites you use to ensure that personal data is stored in a secure method, and that your information is not kept for longer than is necessary.
It's also a good idea to follow Safe Password Practices to ensure that you won't be badly affected, if your information is hacked.