Yesterday Mark Zuckerberg set off a stampede to Facebook's newest app, Friendsheet, by 'liking' it on his page. If you followed him there you found a page almost visually identical to Pinterest, but containing only the photos your friends have recently posted.
Friendsheet looks like it has the same potential as everything else Zuckerberg touches. With so many people flocking to Pinterest to while away the hours, this will be an easy transition to bring them back to Facebook.
The app gives you the opportunity to share, like and comment on your photos directly from the page. And it does so much more smoothly than Hootsuite, Tweetdeck or Nutshell. Since you are performing the action internally from Facebook instead of from an external platform everything works much better.
While very similar in appearance and interface, I don't see Friendsheet overtaking Pinterest anytime soon. Friendsheet is strictly social. Pinterest started out with the intention of curating a collection of your personal favorite images/links for your own organizational purposes, and now business are trying to turn it into a social networking vehicle for promotion.
They both serve their own purposes and will continue to grow and evolve as users define what they want out of each platform.
For more info, check out AllFacebook.com, the Unofficial Facebook Resource.