How search engines work
The Index
Ever wonder how Google can search the entire web in less than a second to find what you want, yet it can take minutes to find a file on your own computer hard drive? It's because Google doesn't search the web! It searches an index that's created and updated on a continual basis by automated programs called spiders, crawling the web, and collecting information. The spiders feed info into a program that parses it (chops it up into managable bits), and hands it off to the index for filing.
The index is a bit like a spreadsheet, only a lot more complex because it can reference information hundreds of ways instead of just by rows and columns. To get a better idea of how google sees a website, google offers a set of webmaster tools, one of which allows you to see what the googlebot sees when it spiders your site. Once the information is parsed and indexed, it’s ready to be searched, and to do this, the search engine uses it’s search algorithm.
Search Algorithms
The search algorithm is what each search engine uses to determine which sites are the most relevant to the words we type into it. Each engine has it's own secret algorithm, but understand that the only goal of any search algorithm is to give you what you ask for as precisely and quickly as possible, since the popularity of the search engine depends upon how well it does that job.
In the early days, a simple search algorithm might just count the number of times your search term was used on a certain page and direct you to the page with the most occurrences of that word or phrase. But the web grew in size and complexity, and site owners soon learned they could easily manipulate these simple search algorithms to direct people to their sites, so search algorithms have evolved also. They analyze hundreds of factors now and have an almost human-like ability to understand what we ask for and deliver relevant results. If your site is truly relevant to what a web surfer searches for, your site will pop up somewhere within the SERPs (search engine result pages), and this is why a ranking report can be so useful, since it tells you where you rank currently.
If you’re not ranking where you want to for the search terms you’d like, you’ll need to first optimize your pages for the terms that you want so that search engines will know that your site is relevant to the terms you want. More may be required than this, but you won’t be able to get off the ground without this first step.
