So what's the downside? One day you might come home and your email box may have more junk mail than your regular mail box. While it's difficult to completely stop your private email address(es) being exposed to strangers, you can certainly try.
One way to handle this problem is to get a secondary email box and use it to send mail to "public" places, while using your primary email address to communicate with your friends and family. If your secondary mailbox starts to receive too many junk mail, you can simply close it or change it's name. Many Internet service providers (ISPs) give you the option to open a second mail box for a one time fee. If your ISP doesn't provide you with this option, ask if they would at least create an alias for your existing mail box.