The projector displays what is open on the computer and, rather than using a mouse or keyboard (although you can use those also), the SMART Board is a touch screen, which allows you to manipulate anything on the screen using your fingers.
Uses of Smart Board:
Technology in the Classroom: Smart Boards Enhance Students' Learning Experience. It can provide students with an enriched learning experience by projecting visual elements. It also makes differentiated learning much easier because teachers are able to accommodate different learning styles.