Reply by RonInOhio

SEO is Search Engine Optimization. Its used for getting your site indexed higher up within search engine results, so your page isn’t buried 20 pages back or more.

Typically and quite simply the keywords (tags) or meta info in your page is compared by the search engine for a particular relevance or match to a search term.

There are whole books and many so-called experts that specialize in optimizing a web site for better rankings on search engine results.