Most of the people here might be using Google as their primary search engine. You got any doubts, ask Google. Nowadays, google has become more of a verb. Googling seems fun. When on one side Google is so popular, many people don't know the utility of the 'I am Feeling Lucky' button on the Google homepage. Let me clear it for you.

When you do any google search, google displays a list of options on the next screen. Depending on the popularity and SEO of websites, they appear in a particular order. The algorithm for that is defined in the source code of Google Spiders or its web crawlers. The 'I am feeling lucky' button is more of a 'luck' factor. If you believe that the FIRST website or link which Google will display is the one you want, Hit this button. It will automatically open the FIRST search result rather than displaying the complete list. This works when you are determined that the keywords you input are accurate and the source of information you are looking for is very popular and likely to be the Primary Result. Try it!