I saw this a few days ago. Now, it has a video to demonstrate it. Using an unlocked Windows Phone (with Mango of course), the developer has created a folder app.
It can store your favorite apps in one folder. I think this is a very neat way to arrange your apps. Microsoft should have thought about it (or they already had?) during the Mango update.
The app is not ready for download yet. However, here is a proof of its existence.
If you can’t wait, you can stalk Windows Phone Hacker (@wphonehacker) for his latest update.
[ad#img]
[ad#boxlist]