SEO stands for Search Engine Optimization and it’s an industry created just for obtaining higher ranking on the Search Engine’s search pages. Since Google is the number one search engine, SEO’s are mostly patterned to get a higher ranking on Google searches. This should give you enough information to know what SEO is, but there’s a whole industry out there devoted to doing just that. Imagine that thousands of companies out there are making a living optimizing web sites to rank higher in search engine results or claim to be designing web sites specifically for that purpose.
There are many computer savvy people who get sold on tackling the job of designing their own website. They may know how to get around their favorite word processor program easily, however, html maybe a different story. The forums and help websites are loaded with requests for help or questions regarding various problems they encounter. In the meantime, the website design is delayed till the problems are resolved or seek a professional web designer.