Do not use personal email accounts to transmit others' private information. There's a big difference in privacy and safety between a "business-class" email service and most people's free web email. Big organizations put a lot of effort into making their email systems safe (or safer) because they know there's a lot of bad email out there.
To reduce the value of your contact information among advertisers, add your name to the 'Do Not Call/Email' lists. Even though it may take a little while for advertisers to pick up the change, it's a good and easy step. There may still be hackers or less careful advartisers out there who don't pay attention to 'Do Not Call/Email' lists, but when your name's on a list it's not worth as much on the black market.
Disable cookies in your internet browser. "Cookies" are data files stored on your electronics that track your internet browsing activity. To minimize the tracking of your internet browsing activity, be sure to limit or disable Cookies in your browser options. The links below show how to do the steps in various browsers: