Webapp Sortbox adds a new folder to your Dropbox. Any new file added to that folder is automatically moved and organised based on rules you define, which makes it handy for keeping your files organised.
First, you authorise Sortbox to access your Dropbox account. Then you create rules based on a file's extension name, file type, or other pattern. When a file matches one of your rules, Sortbox moves your file to a folder of your choice inside Dropbox. That's all it does, but it's a good way to get low-hassle organisation.
It's free to use, and looks like a solid option for automating Dropbox folder organisation. If you want a little more power, I'd recommend checking out Belvedere or Hazel. Our previous guide to automatically cleaning and organising your desktop with either app will get you up and running with those in no time.