Hello,
There are a lot of reasons why you may be receiving SPAM emails. Usually, when you put your email address in a page, a lot of bots might be able to easily get your email address and share them with individuals or companies for marketing purposes.
The good news is, a lot of websites can protect you with that. I will be referring you to ProjectHoneyPot which contains a better explanation with what is happening to the both of you.
www.projecthoneypot.org/about_us.php
Let me know if you have any other questions.
Thanks.
