I talked with MooN and I can assure everyone that your email addresses have never been sold or used for any purpose.
Spamers have written spam bots specially designed to extract email addresses from bulletin boards such as this one. The spam bots craw through posts and go to your profile where your email address is displayed and then harvested.
An option to protect yourself against the spam bots would be to edit your preferences under the option “Keep your email address viewable to others when you post notes?” Set that option to “No” and the spam bots will not be able to harvest your email though your profile. Also make sure never to reveal your email in any posts or signatures or the spam bots will harvest it.