can use one for a different function that the otherIt's depend of your wish and graphic card driver. Normally after expanding your desktop you will have screen 2560x1280. It's fantastic for daily use. For example on one screen you can have Word, and another Excell. It's very comfortable.Or you can use special mode for PowerPoint. First screen with presentation and second with your conspect and handout.But if you wish show another person same information which you can see on your screen, also no problem. it's mode when both screens display same informationIf you notebook, you can connect second screen, LCD projector or even TV.With desktop computer you need dual head card.It's all and it's worth use two screens. I have occasion to test 21" LCD screen with 1600 dencity. But I prefer two small 1280x1040 LCD. They are much more comfortable.
