Search Engine Optimization (SEO) is the process of optimizing web pages or whole sites in order to make them search engine friendly, thus getting higher positions in search results.


How Search Engines Work

Crawling

Process of fetching all the web pages linked to a website. This task is performed by a software, called a crawler, spider or Googlebot.

Indexing

The process of indexing is identifying the words and expressions that best describe the page and assigning the page to particular keywords.

Processing

When a search request happens, the search engine processes it, and compares the search request with the indexed pages in the database.

Calculating Relevancy

The search engine starts calculating the relevancy of each of the pages in its index to the search string.

Retrieving Results

The last step in search engine activities is retrieving the best matched results. Basically, it is nothing more than simply displaying them in the browser.

Algorithm

Search engines such as Google often update their relevancy algorithm dozens of times per month, so when you see changes in your rankings it is due to an algorithmic shift.