So, what happens when your website has reached number one or two on Google, and perhaps Yahoo! as well? You sit back and reap the rewards and live happily ever after? Sorry, to put a damper on things again...
It is important to understand what the search engines are trying to accomplish - aside from making money, or better, in order to make money. They, and Google truly is on the forefront in terms of development, evaluate, rethink, and reprogram all the time. The idea is to present RELEVANT information to users. A blog owner who tells you four times on one page to take a hike probably isn't what you were looking for when searching for 'trail hike'. So, search engines change their criteria and methods used to interpret, evaluate, and place websites.
What that means for you and for us is, that SEO conditions and requirements change. What was acceptable yesterday may not be tomorrow. What was perfectly good and successful SEO practice last year could be completely irrelevant by now. What works for one search engine does not with the next. And so on. And, let's not forget about your competitors; they also have discovered SEO and did some work on their websites.
So, the answer really is ongoing SEO. Give your statistics a good read, check your own website out in several search engines (but think like a potential customer - one who may not know your company name or technical terms), make a list of your most important key words and phrases, and compare where in search your website comes up. You should probably do so every 4-6 months. Then contact us with the results of your findings; we will go over it together, make a plan for improvement, and go over everything with a fine tooth comb again. Alternatively, we can do all the preliminaries for you, of course.