http://blogs.adobe.com/photoshop/2013/09/introducing-adobe-generator-for-photoshop-cc.html
When you create apps for various sized mobile phones and tablets, there is a requirement to create icons and splash screens of different sizes – Sometimes up to 20. The sizes are very important and need to be accurate. There are some very nice templates around that use actions to output the various sizes required. When I looked at one of the templates and it referred to Adobe Generator to automatically create the graphics files, I was intrigued. Now I have seen it in action, there is no turning back.
Basically by turning the generator on, it will create image files for each layer that you name with a valid file suffix, like .jpg or .png. It does this on the fly without you needing to create slices, or output layers individually. Click on the link above for a blog post that provides a lot of detail on how you can use this feature to save time.