also known as Search Engine Optimization (SEO), is a phrase to describe the practice of positioning a web site within the search engine results. A multitude of techniques are involved in successful search engine positioning. Not only must a web site be optimized, but it's link popularity must also be built. Good visibility in directories must be gained and other search engine marketing techniques pursued, such as Pay Per Click campaigns. Search engine positioning has evolved over the last few years. While initially involving only search engine optimization, the industry has grown to include a whole array of additional techniques.