Search Optimization: the Battle.
Imagine that Google is a hill - (go with me on this). The top of the hill is the first page - the number one place to be seen. The further you go down the hill, the less likely anyone will find you - recent statistics say that less than 12% of people wander past the first page of Google.
I often hear people think that once you optimize for the search engines and reach the top of the first page, you're done and declared the winner. If only it were that easy.
Imagining Google as a hill is useful because once you reach the top page of search results, you look down and there are thousands of competitors reaching for your place. If you think your competitors around the world that are on page 2 through 200 aren't working each day to beat you, you are mistaken.
It's a constant battle.
To reach the top, declare victory, celebrate, and throw your SEO weapons down is about the worst thing you can do. You will be overtaken and pushed way back down again.
Stop viewing search optimization as a single project with a completion date. It's a constant process of fighting to be king of the hill - that important number one position in Google searches.
To learn more about how you can be king, read the article What does my content have to do with SEO? and also check out this great resource at Moz.