Why this is important?
As said, not everyone gonna need it. But since most of the never Netbooks or display screens in general have very sharp DPI settings (because those pixels are fixed into a smaller screen size) thus things may look a little too small and if you've been used to seen big text and windows "thanks" to your previous old computer... then you can certainly try changing the DPI in Ubuntu (or any other OS in that instance) to try to make things look a bit bigger.
Accessing DPI settings in Ubuntu (or in Gnome classic desktop to be more accurate) is fairly simple. And I'm pretty sure almost all the Ubuntu (or Gnome geeks) know this... but if you're a bit new to Ubuntu and wondering ... then this is how you do it.
1. Just right click on your desktop and choose "Change Desktop Background".
2. Then click on the "Fonts" tab and under the sub heading "Rendering" click the "Details" button which should open-up a window similar to the below one.
3. By default Ubuntu or the Gnome classic desktop is optimized for the 96 pixels per inch but you can lower or increase the value to make things look more smaller or bigger.
But remember. the best possible (meaning sharp and clear windows, buttons, etc) setting for your OS is the default DPI that it comes with. And if you go below or beyond this "default" value that it's optimized for... then things may not look that sharp. But you can try lowering these values here and there ... you know experiment a little.
You can also use this window to optimized font rendering settings to enhance their readability as well.
|Remember the "magic number" ;-)...|