The concept of object oriented CSS and how it can help improve both the performance and maintainability of your Web pages. As with any object-based coding method, the purpose of OOCSS is to encourage code reuse and, ultimately, faster and more efficient stylesheets that are easier to add to and maintain.

Almost every element on a styled Web page has different visual features (i.e. “skins”) that are repeated in different contexts. Think of a website’s branding — the colors, subtle uses of gradients, or visible borders. On the other hand, other generally invisible features (i.e. “structure”) are likewise repeated.

Benefits:

• Faster Websites
• Maintainable Stylesheets

More info @ SmashingMagazine