Quite possibly the coolest addition to the internet since the API and standardized REST based services... A tool that opens up Web App API's to everyone, by connecting services to each other with hooks and actions.
So you were tagged in a photo on facebook, and would like to have a copy on your computer? Go in to facebook, open photo, click download photo, find folder, save.
Sign up for the recipe "Download Facebook Tagged Photo" and every time you are tagged in a photo, it will automatically be uploaded to your Dropbox, and thus magically appear on your computer.
This app is going to be the glue that finally allows for some coherence among disparate web services.