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.
help you get data about crawling, indexing and search traffic.
This tool will let you know how many people find your website through Google search result, and how many people surf your website through the result, and what kind of key words they used to search.
You can associate your Webmaster Tools data with Google Analytcs, it will then be able to display some of that data in some reports. You can apply setting in "Property Settings" function page after you sign in.