All your lists (including Collection and Wantlist) are private by default. To make them public, go to your profile page from the dropmenu under your username, then Settings in the left column. Check the boxes next to lists you’d like to be made public (you can also share your Read, and Following lists). Save Settings. Now anyone with the URL - whether you share it on social media or directly with a friend - will be able to see what’s in your Collection and Wantlist.