Once you’ve installed the Stylish plugin into Firefox, you’ve opened the world to a whole range of user created interfaces and application interface tweaks on the Stylish directory that would simply be impossible to do otherwise (unless it’s an open source app and you’ve got some coding knowledge).
Don’t like the look of your sidebar in Google Reader? Then simply download one of the many “styles” that users have created for that particular application and the look is instantly altered. When you download a style, there is an option to preview how it will make your application look although this didn’t work for me. However, installing and removing styles is so quick and easy that you don’t really need this option – style changes are instantaneous.
The only drawback of stylish is the way that some users label and annotate their different styles. Some of them don’t really explain (or show a screenshot) of how the application will look when you’ve altered it which means the only way to find out is to download it. I was actually looking for a way to extend the subscription sidebar in Google Reader so that I could see all my subscriptions without having to scroll down but despite trying several styles, drew a blank. Currently popular styles include a dark grey interface for YouTube, an improved Add Bookmark dialogue and an alternative look for Gmail.
However, the sheer number and range of applications and programs you can change with Stylish is truly impressive – chances are, if you want to change the look of an app or program, you can with Stylish.