Search engine optimization (SEO) has been around almost as long as the search engines themselves. SEO refers to the process of trying to make a site rank well for particular keywords in the search engines. There are quite a few factors involved in making a site SEO-friendly. Some are on-site factors such as using the right keywords and having an internal linking structure, site map, meta data and alt tags, and optimal URL structure. Other factors are off-site, such as trying to encourage other sites to link back to a site and increase its inbound links.
While some SEO tactics are longstanding in the SEO community, such as creating high-quality engaging content so users link to a site naturally, the SEO field by its very nature is constantly changing. A top SEO expert thus has to constantly remain abreast of the latest nuances and often learns by trial-and-error and conducting tests.