In the old days, a Web site usually consisted of static HTML pages and perhaps a few images to liven up the text. No more is this the case - sophisticated interfaces, streaming media, dynamically-generated content and other enhancements have all contributed to make today's Web more content-rich and interactive than ever before. Most often, this is a Good Thing - greater accessibility and more quality content only make the Web more attractive to new users, and increase its usefulness to the community at large.

However, there is a downside to this phenomenon as well. As sites become more content-rich, as their reliance on dynamic data sources increases, as their servers struggle to meet the thousands of requests coming in per minute, it's only natural that the first casualty be the performance of the system. This is clearly visible in the Web, which today more closely resembles a slow traffic jam than a fast-moving freeway.

Fortunately, there is a workaround, one that has been successfully used by many sites to provide a performance improvement: caching. And over the course of this article, I'm going to show you a few examples of this technique in action, using my favourite language, PHP, and an open-source implementation of a server-side cache called Cache_Lite. Flip the page, and let's get started!