There is a new row on the puzzle detail page to help track where your puzzles come from.
Once a puzzle is in your collection, you can keep track of where you got it from. You can select an existing user of the website, add someone using an email address or mark that you purchased the puzzle new or from a thrift store.
When you exchange puzzles with someone on the site, this information is automatically set for you. But you can change it or remove it if you like.
On your profile page, you can filter the puzzle list to see the puzzles based on where you received them from.
Just another tool to help you keep your collection organized.