So they’re creating Secret Boards (presumably just for the Holidays). Via Pinterest:
The holidays are a time for being with family, sharing great meals, and, of course, surprising your favorite people with a special gift. That’s why we thought the holidays were a perfect time to test one of our most frequently-requested features: secret boards! Starting today, we’ll be gradually rolling out a test that enables anyone to create three secret boards.
We hope that secret boards will make Pinterest even more useful. You can use secret boards to keep track of holiday gifts, plan a special event, or work on a project you aren’t yet ready to share with the rest of the world. You can keep your secret boards to yourself or invite family and friends to pin with you.