A story at The Economist named Dancing with Google's spiders (subscription required) talks about how SEOs work to achieve top rankings for their clients on Google. Here is the free abstract;
The industrious spider bots that crawl around the web on behalf of Google, the world's biggest search engine, evoke both fear and reverence. Late last year the bots swept through the world's web servers to scrutinise some 8 billion web pages and determine their new rankings in Google's search results. As Google tweaks its mighty ranking algorithms, and applies them to the constantly changing pages of the web, different sites shuffle up and down wildly in its search rankings, repeatedly gaining and losing ground.…
Like hurricanes, Google Dances are given names, such as Bourbon, Gilligan, and Florida, often by commentators at a website called webmasterworld.com.
Matt Cutts, a senior engineer at Google who is assailed with algorithm questions at industry conferences, says his firm like its competitors, carefully controls access to its secrets. ‘A lot of our best ideas don’t get filed as patents because patents eventually become public.
The most powerful determinant of a webpage’s importance is the number of incoming referral links, which is regarded as a gauge of the site’s popularity.
Unethical methods, known as ‘black-hat SEO’, including renting links from popular or long established sites (their links carry more weight). Some unscrupulous SEO outfits even exploit loopholes in website-managements tools to place hidden links on prestigious sites, such as those maintained by universities.
Is SEO becoming a household name? It is just amazing watching this industry grow.