Understanding Search Engines

How SEO Works

SEO (or Search Engine Optimization) is an inbound marketing channel. In essence, the purpose of SEO is to position your website to catch inbound demand coming from search engines, like Google, Bing, Yahoo, etc. In order to catch this traffic, you need to optimize your website to rank for specific search terms. As a general rule, the higher you rank for specific terms, the larger the share of traffic (or clicks) you’ll get from that term.

Understanding SEO Guidelines and Best Practices

Therefore, in order to do SEO the right way, you need to understand the guidelines that each search engine uses to rank websites / web pages when someone searches for a term. It’s important to note that these are just guidelines, not hard and fast rules. Google and other search engines do not publish the formulas (called algorithms) they use to rank websites. They simply offer guidelines on what they value.

In addition to these guidelines, SEO experts have put together a list of best practices for optimizing a website to rank higher. These best practices are based on observable results correlating with specific tactics SEO practitioners have implemented to rank higher. Through the process of trial and error, SEO experts have learned what works and what doesn’t. And, in this white paper, we’re going to share some of these tactics with you.

The Changing Nature of SEO

It’s important to note, however, that search engines are always changing the rules of the game. Their No. 1 goal is to connect searchers with the best information relating to their search query. And, as SEO practitioners have found ways to game the system, Google has made adjustments to penalize sites engaging in these less than honorable tactics (often referred to as Black Hat SEO tactics).

A big part of SEO isn’t just doing what works, but doing what’s sustainable and what follows the general guidelines of Google and other search engines. Taking shortcuts can yield short term results, but can hurt you tremendously in the long run.

Therefore, SEO will always be an ongoing process that requires you to stay abreast of the latest updates and focus on optimization that offers better experiences for searchers.

How Search Engines Work

Early Search Engine Algorithms

In the early days of search engines, optimizing your website was a much easier process. In fact, some of the earliest search engines were controlled by editors and would put websites into directories by topic, listing the websites within those directories in alphabetical order.

As time went on, search engines evolved as part of their quest to connect searchers with the best results, and as they evolved, SEO became more and more complicated. Their next step was to rank websites based on the words used in the site. If you were searching for “vacation rentals,” the site that had the most instances of that term throughout the content of their website stood a greater chance of ranking higher. But, what search engines soon learned is that when you rank a website purely on keyword relevancy, it’s easy to game the system. And, consequently, when people game the system, the results returned in searches do not meet the needs of the searcher.

Google Revolutionizes Search

The biggest breakthrough in the history of search engines came in the late 1990s when two Stanford students, Larry Page and Sergey Brin, came up with the idea to build a large-scale hypertextual web search engine. Their idea was revolutionary in multiple ways. It not only allowed search engines to draw from a much larger portion of the web, but also used the connections between these websites (hyperlinks) as a factor for ranking websites in search results. Page and Brin theorized that when one website linked to another website, it was a sign of trust – like a vote of confidence in the website they were linking to. And, Page and Brin theorized that they could use these votes of confidence to assign a level of authority to websites, that when combined with keyword relevancy, would yield much better search results.

Page and Brin went on to found Google in 1998. Their ideas, outlined in their Stanford paper ” The Anatomy of a Large-Scale Hypertextual Web Search Engine,” became the foundation of Google’s search algorithm. Many of those basics concepts are still very relevant today.

Indexing the Web

But, in order to execute their ideas and use them to build Google’s search platform, Page and Brin needed to build a large scale map of the web. This map is now known as Google’s index. Understanding how Google indexes the web is crucial to understanding how search engines work and how SEO works.

When you do a search on Google, you are not searching the web itself, but Google’s index of the web. Essentially, Google is the world’s best matchmaker. It knows everyone, who’s most important, and the best ways to connect you with the right person. Their index is like their little black book, but on a massive scale. Knowledge is Google’s is greatest resource, and it has more than anyone in the world. In fact, Google’s primary goal is to organize the world’s information.

So, how does Google collect the information it uses to build its index? It employs programs known as crawlers (or spiders) that are constantly moving from one website to another, via the links on these websites. As they crawl from one website to another, they record information about the websites and their relationship to other websites.

As the map of the connections between these websites becomes clearer, Google uses an algorithm to see which websites are getting more links from other websites. And, as Google further understands the connections, it can even weight the value of links from one website to another based on how authoritative that site is (i.e. how many links it has). For example, a link from a website that has a lot of back links might be worth 10 times more than a link from a website with not that many back links.

Link relevancy also plays an important role. Links from websites that have similar content or cover similar topics can help influence a website’s rankings for terms relating to that topic area.

In short, Google’s search algorithm works because it contains massive amounts of information about the world’s websites and their connections to each other. And this information is what Google draws upon to serve up search results. Over the years, Google has made adjustments to HOW it draws upon this information, but the index itself is always the starting point.

For a better understanding of how search works, check out Google’s Interactive Story online.