Search Engine Optimization (SEO)  is the process of improving the visibility of a website, more frequently site appears in the search list, the more visitors it will recieve Google served these tools just like a bread and butter and interesting thing is all this stuff is free. SEO is very important when you are building and maintaining a website and for this Google Offers Number of Free Tools which are getting popular day by day.

List of Free Tools By Google.

• Google Keyword Tool .: Most popular tool by google, serves a great help in selecting the right and most effective keywords.
• Google Analytics .: Another popular tool not only lets you measure sales and conversions, but also gives you fresh insights into how visitors use your site, how they arrived on your site, and how you can keep them coming back.Google Analytics is built on a powerful, easy to use, reporting platform, so you can decide what data you want to view and customize your reports, with just a few clicks and  helps you measure the impact of mobile on your business.
• Google Website Optimizer .: With Website Optimizer, you can try any combination of content to find out what leads to the most conversions.Testing makes it easy to increase your site effectiveness and visitor satisfaction, which leads to higher conversion rates and a higher return on your investments.
• Google Webmaster Tool .: Very popular tool gives you detailed reports about your web pages’ visibility in Google search. The traffic coming in wouldn’t tell you WHICH websites it’s coming from, which is where Webmaster Tool shines! You can also see how the site get indexed to the search engine also the problems the google is facing with your site and allow measures to fix the issues as well.
• Google Traffic Estimator.: Another popular tool by google, using this tool one will get to know about the Average Estimated CPC,Total Estimated Clicks on a website, Estimated Ad Position and Estimated Daily Cost.
• Google Trends  .: With Google Trends, you can compare the whole world’s interest in the topic of your choice. You will get to know how often the topic is searched how often they show up in Google News stories etc etc.

All the above tools are free can boost your website very easily.The thing is you got to target correct keywords by using the tools listed above and google will deliver you the desired results