Search Engine Optimization or SEO for short, is simply a legal and efficient means to get one's site presence known by raising its search engine ranking so it gets seen more often then not.
This is all possible by optimizing one's site with proper SEO friendly keywords and tagging which leads to a better ranking in terms of pages overall.
This is a reliable and a great way to get yourself known.
SEARCH ENGINE OPTIMISATION
“Good SEO work only gets better over time. It’s only search engine tricks that need to keep changing when the ranking algorithms change.” – Jill Whalen