Google Webmaster Tools is a excellent way to track keywords, broken URL's and much more activity on your site. It's a great free tool from Google to help you get simple data about how users are finding your site or linking to your site. While it is not as advanced as Google Analytics it works slightly differently by giving you information about how Google Search Spiders crawl your site.
In this video I show how you can add a MemberGate site to Webmaster Tools but this is the same for any site although you will need to upload you own file to your site using an ftp program.
The quality of the video is a little poor, I apologies for that as I recorded it at the wrong screen size and then YouTube re-sized it again but the content and information is still the same. You can watch it and then add your own site for tracking.
Firstly signup for a Google Webmaster account then view the video below.
To get more up to date information about Webmaster tools I suggest subscribing to their blog feed and also reading some of the articles. As mentioned in my video Google have simplified the verification process but you still need to upload the file to your site.