Google  and SEO

Google is constantly working to ensure that when someone uses its search engine, that the results list websites in the correct order (e.g. the most relevant and best websites are listed first). When Google changes the order in which websites are listed, this is effectively because Google has changed its mind about which websites are most interesting to people doing searches. If your website is position 10 in Google for a given topic, then Google thinks that your website is the 10th best website on that topic. If tomorrow your website goes to position 5, then that is because Google thinks you have improved your website so that it is now the 5th best. Alternatively, if you drop to position 15, that is either because Google thinks the quality of your site has gone down, or it could be because the quality of some other sites has improved in Google's opinion so that they are now more relevant to visitors than yours.

In fact, the order in which websites are listed is constantly changing, partly in response to changes on the websites, but also because Google is constantly changing the way in which it calculates website quality, in an effort to give more and more accurate results. The reason for this is that the more accurate and useful the search engine results are, the more people will use their search engine. If the results of the Google search engine are inaccurate (e.g. list low-quality sites before high-quality sites), then people will use other search engines instead (e.g. Yahoo, MSN). Google does not want this to happen, because the more people that use its search engine, the more money they make from selling sponsored advertising. This is why it invests a large amount of money to constantly improve its search engine, and then allows people to use it for free.

Consequently, to have your website get a top ranking in Google for a given topic (e.g. French real estate), all you need to do is show Google that your website is the best website on this topic. Google will then naturally list your site first, as they want to list the best sites first, so that more people will use their search engine, and they will then make more money. The topic of SEO is all about how to convince Google that you have a great website.