This tool uses Photoshop Custom Shapes extension that generates vector wireframing shapes. It can be useful for all designers that use Photoshop as a primary graphic tool. The main idea is if you use Photoshop to design web sites and other projects it is also very handy to use Photoshop for wireframing and prototyping. With this tool now you can easily mix vector custom shapes with the Photoshop native functionality. For now there are about 100 vector / custom shapes that you can use for wireframing.
Clipping is a handy way to collect important slides you want to go back to later.