This video demonstrates how to use a computer (mac or PC) with up to 3 displays via VGA or DVI.  The computer only requires one monitor out via VGA or DVI (depending on which model you choose).  How this works is that all of the monitors havve to have the same resolution across the moitors (say 1440×768)… to the computer it appears that it’s one monitor at 4320×768.  This device isn’t for high-performance gaming but is great for spreadsheets, office, web, etc.. just don’t try gaming with it.