A good quality of search engin optimisation is essential to get a sustainable presence on search engines’ listings (especially Google). It has to be considered before any website project. An efficiently optimized referencing can generate quality traffic during your website’s lifetime. In other words, if you are selling male shirts, you don’t want to attract people looking for female shoes.
The main constraint in SEO is that it is hard to have a full control! Google has always the last word. It is Google that evaluates the various selection criteria and that classifies search results using its algorithm, which is often modified and optimized.
Nobody can control what is going to be in the first result pages of the search engine (we recommend stopping working with any individual that say the opposite!). The best strategy for referencing is to be the best player according to Google’s rules, which means to keep tracks of the evolution of those rules. It is a necessity if you want to have the best listing position possible for your firm.