There are lots of ways that we get junk mail. Anytime you post your email in a forum or blog or community (like AR) you leave yourself open for more of it. One way that you can do it safer is to use words instead of the symbols in your address.
Example: chad at insertrealestatecompanyhere dot com
If someone legitimately wants to contact you, they can. They will take the time to 'edit' the address listed so that their message will reach you.