This website uses Google AdSense to serve ads. Specifically:
The first time you sign into this website, the external authentication providers used by this website (Google and Facebook) will give your email address to this website. This website will not share your email address with other users or anyone else. If you are really concerned about protecting your email address, you may delete your email from your profile page. However, some optional features, such as receiving a daily/weekly email about new cards created by people you follow or other people "liking" your cards, will not work.