Finding useful and informative content on the World Wide Web is something that many of us take for granted. There are near about 150,000,000 active Web sites on the Internet today, according to the Internet research firm Netcraft. The task of filtering through all those sites to find helpful information is enormous. That's why search engines use complex algorithms, mathematical instructions that tell computers how to complete assigned tasks to it.
Google's algorithm does the work for you by searching out Web pages that contains the keywords you used to search, then assigning a rank to each page based on several factors and techniques, including how many times the keywords appear on the page. Higher ranked pages appear first up in Google's search engine results page (SERP), which means that the best links relating to your search query are theoretically the first ones Google lists.
For Web page administrators, being listed prominently on Google can result in a big boost in site traffic and visibility. In 2007, Google declared Microsoft as the most visited site on the Web [source: The San Francisco Chronicle]. With that much traffic, getting a good spot on a Google SERP could mean a huge boost in the number of site visitors to your website.
Google's keyword search function is almost similar to other search engines functionality. Automated programs which are called spiders or crawlers travel through the Web, moving from link to link and building up an index page that includes certain keywords matching with the search keywords. Google references this index when a user enters a search query. The search engine lists the pages that contain the same keywords that were in the user's search terms. Google's spiders may also have some more advanced functions, such as being able to determine the difference between Web pages with actual content and redirect sites pages that exist only to redirect traffic to a different Web page.
Keyword placement plays a crucial part in how Google finds and indexes sites. Google looks for keywords throughout each Web page, but some sections are more important than others. Including the keyword in the Web page's title is a good idea, for example. Google also searches for keywords in headings, title of the page and name of the file. Headings come in a range of sizes, and keywords in larger headings are more valuable than if they are in smaller headings. Keyword dispersal is also important. Webmasters should avoid overusing of keywords on a page, but many people recommend using them regularly throughout a page as Google disregards it.
Also read: Google Maps can track You