How Do Search Engines Rank Websites?

How do search engines place websites in their rankings?

You've probably heard that when someone makes a search on Google, if you're not in the first few web pages that appear in the search results, it is unlikely that you're site will be visited.

When someone makes a search on Google or any other search engine, there are potentially millions of web pages that can come up. Search engines therefore need to have a way of determining which of these pages are the most relevant.

Each of the major search engines have come up with their own methods (algorithms) for determining a page's relevance to a particular query.

In general, they consider the following:

Link Analysis

Every major search engine uses link analysis in ranking web pages.

In general link analysis involves evaluating the links to your website from external sites (back links). Link analysis also considers the following:

Link context i.e. the relevance of the link in relation to the user's search query. 

The "importance" of these external website in the eyes of the search engine 

The number of external websites that link to your site

Keyword density, frequency & location

Keywords, for example "cheap flights," are words that people use when searching for a particular business, product or service. Where and how often keywords are used in the content of your site will impact your search engine ranking. If you are in the business of selling cheap airline flights, you will want to make sure that your site ranks well with search engines when a user makes a search using these kind of keywords. In general, the following factors can impact search engine rankings:

Keyword density - how often a keyword appears on a page (as a proportion of its length) 

Keyword frequency - how often a keyword appears on a page (without it being deemed search engine 'spamming') 

Keyword location - where a keyword appears on a page (e.g page title, top of page, bottom of page, etc)

If you really want to know what makes search engines like Google tick, see Sergey Brin and Lawrence Page original paper, The Anatomy of a Large-Scale Hypertextual Web Search Engine.