Search Engine Optimization (SEO) for Absolute Beginners Part 2: How do Search Engines Work?
Welcome to part 2 of my multi-part series of posts on Search Engine Optimization for Absolute Beginners. In part 1 of the series, I talked about why SEO matters. Today, I'll explain, in vastly oversimplified terms that would drive a Google engineer nuts, how search engines work.
Search engines crawl the web like a hyperactive spider. They start on a web page, then follow every link on that page. When they get to a new page, they follow all of those links, and so on. By doing so, the search engine builds a list of every page it can find and a knowledge of what's on those pages.
Now that the search engine is sitting on this giant heap of pages, it has to make sense of what all that content is about. By content, I mean not just the text of pages, but also the way that text is organized and connected with other pages on the web. For example, something in big bold type at the top of the page is probably a more apt summary of what's on the page than than some small text at the bottom. Again, I'm talking in gross generalities here, but understanding the general concepts will provide you a better foundation for the more specific, tactical lessons of SEO.
There are also other "on page" factors that search engines look at. When you create a web page, bits of code called "meta tags" also help search engines determine the content of your web site. Having a relevant term in your URL also helps (one of the reason I named my Baby DVD "That Baby DVD" is so I could rank for the term "Baby DVD"). Search engines also don't "see" pictures when they crawl, so it's also good practice to give your images text-based descriptions as well.
It's important to know that search engines don't treat pages in isolation. As important to your search engine rankings as what's on the page is the quantity, quality, and description of links to your page from other pages. Let's break that last statement down a bit. It's important.
Quantity - The number of pages that link to your page is used by the search engine as a proxy for its authority. Lots of people link to stories on TechCrunch, so search engines are likely to see TechCrunch as a site with relevant content.
Quality - Are the pages linking to you low traffic sites with ads for male enhancement products? Or, are you getting "link lovin'" from authoritative sites like The New York Times or Digg?
Description - A link featuring the term Unique Baby Gifts is better than just http://www.thatbabydvd.com or even worse, click here.
In summary, search engines look at both "on page" factors of what's written on your page and how it's organized and "off page" factors of who links to you and how they do it to "understand" the importance of your web page an match it to a search for a given term.
In the next installment, I'll tell you how to use your newfound knowledge of how search engines work to rank better for terms related to your site.


