Is it possible to use more than two monitors in Ubuntu?
If so, which graphics cards are known to work for example with three monitors in Ubuntu?
Ordinary graphic cards support only up to 2 monitors. Laptop usually support own monitor (LVDS) and one external (VGA/DVI/HDMI), while desktop has 2 monitor ouptups.
You can use more graphics cards if your motherboard and graphics card support. Example: http://www.youtube.com/watch?v=N6Vf8R_gOec
Some (newer) ATI cards support DisplayPort and you can use more monitors (I don't know how much exactly). As you can see in upper video, there are 24 monitors and only 4 cards which means 1 card for 6 monitors.