Webmasters strive to ensure that their sites remain high in search results and they have many tricks up their sleeve to achieve this. Many of these tricks are visible to the average web-user; keywords placed careful within we-pages that allow search engines to view and index the content. The techniques might be hidden away in meta-tags. The end goal is always the same: improved rankings in the search results.
Not only this but Webmasters want to assist the search engines to index their sites to ensure that their content meets the right people. In their turn, the search engines want to deliver apposite results and connect those results to the right person.
We know from tracking results that the large bulk of web-consumers click-though to the top three Google search results and being at the top is the primary aim of all Webmasters.
So the relationship between the search engines and SEO houston seo experts is one that is mutually beneficial but fraught with complications. As ever, these complications relate to profit. Because there are huge gains to be earned for the Webmaster, there are some that will go to great lengths to improve their results in the rankings. These techniques vary wildly but spamdexing (littering the site with repetitious keywords and links) and creating zombie-sites around popular search-terms that are filled with links to less appropriate commercial links.
For this reason, the search engines are guarded about the elaborate algorithms that go into indexing, crawling and delivering web-content to the average search query. But SEO is not all Black Hat (using shady methods to generate high rankings in search results to improve coverall click-though rates). For every dodgy Webmaster using underhand techniques there are a higher number out there improving their ranking by filling their websites with highly valued and relevant content and by building sound foundations, through networking, upon which to build strong rankings.
The search engines need SEO. Thy need it because their industry relies on delivering accurate results and SEO techniques help the engines find the content.
As for the future of SEO, only time will tell. For over five years now Google has been generating search results unique to logged-in users and the impact of this development has yet to be seen.