If you searched for "Miserable Failure" in Google, the top result returned was the official website of George Bush. You can rest assured; George was not sitting there tweaking the "meta tags" within his website to include that keyword term. In fact, I highly doubted the term "Miserable Failure" appeared within his website content anywhere.
What happened was that thousands of other websites started linking to George's website using the exact term "Miserable Failure" as the "Anchor Text" of the hyperlinks. Due to the nature of Google's computer algorithm – and the importance it places on incoming links (and specifically the extremely large amount of weight that theyave to "anchor text" at the time) – it started to recognize that this is what George's website was related to.
Sometimes it gained a # 1 position for this term linking linking alone. Pretty funny stuff really. There are quite a few well known instances of this happening. Another one was a competition between people within the SEO industry to see who could rank for "coolest guy on the planet". If you want more examples, just go to Google and type in "Google Bomb" however this should show you how important incoming links were (and still very much are) as a primary search engine ranking factor.
At this same time you could also use a specific search syntax in Google to see exactly how many back links any given website had, and specifically where those links were. Form an SEO perspective, it was dead easy to "reverse engineer" why the top ranking websites were ranking like they were. You could simply manipulate the keyword density of your content pages, and implement a similar link building campaign as close to the high ranking websites as possible. Hey presto – although it did require work – top rankings would not be far away.
As you can imagine, with the introduction of the importance of incoming links, experienced webmasters we're also able to "game" that to their advantage as well. The "Google Bomb" mentioned was a prime example of how this link ranking factor could be "gamed". However, placing more importance on incoming links as a primary ranking factor was the "lesser of two evils" in the way in which Google could rank websites.
It is easy enough for any old webmaster to manipulate the internal components of their own websites (keyword density etc).