To do this:
1. Go to read.rifflebooks.com. At the top of the page toward the left, click your 'Profile' picture.
2. Copy the link that appears in your browser window. It should look something like this, but with a different number at the end: http://read.rifflebooks.com/profiles/1
3. You can paste this profile link in any email, or share on Facebook, Twitter, etc.