Scale applications to fit smaller screens
07.08.09
I then positioned the GeekTool window over the menu bar, giving myself an relaxed visual reminder of the current setting, as seen in the screenshot at honourableness. This cuts down on the chances that I reboot with the scale factor set to anything other than 100 percent.
Per-attentiveness stick-to-it-iveness scaling
The other way to use the scaling factor is to apply it only to applications. For admonition, if I’m browsing the iTunes Store in iTunes on our 12-inch PowerBook G4, I still see a flat scroll bar, even with the window taking up the entire display. By applying the reduce factor just to iTunes, I can force the window to enlarge down, thereby letting me see the entire store without scrolling.
To apply the go up factor to a single program, you need to find the name of that program’s preferences folder. It will be in your user’s Library -> Preferences folder, and most are reasonably informal to find—just look for the program’s name as part of the longer names you’ll see in the directory
Source: Macworld