Advertising your site on search engines like google is not free, since every click you get costs you money.
If you do some search engine optimization, you can get the search engines to like your pages more, and then they will list them in the organic results (the results people see when they search).
You may have heard of this Page Rank thing. It is a google score between 0 and 10, and the higher the number, the better your page is. No one really knows how PageRank is scored, not even Larry Page (one of the key guys at Google). I can show you some simple things you can do to get better search engine rankings, and a better Page Rank.
