Screen Capture and Resolution

I've been recently both capturing and uploading images to my website. Only just realised the benefits of file-> save for web menu item in Photoshop. The tweeks you can make to an image before saving as an optimised web image are wonderful.
For image capture I use SnagIt 8. A great tool. But the resolution of captured images, DPI and ppi, has always confused me. This terrific article helped to lift the fog:
Resolution DeMystified
It also shows how Photoshop can be used to alter images captured from the Web to be published in print.