Last time we have been talking about how you can review health status of your blog or website using Google Webmaster Tools and you must pay attention there if you care the security of your site. If you missed it, read Manage Your Website in Google Webmaster Tools: Part 2. Now we can move on to the next section - Traffic.
Now that was a summary of search queries for a specific period of time. Further, you can dig deeper into available data and find what kind of information searchers were seeking for. Obviously, you will find very useful clues to improve your site.
Here's a helpful video explaining how you can use GWMT search query information to improve your site. You can find the opportunity hidden in statistics ;)
Links to Your Site
Who Links the Most
Your Most Linked Content
How Your Data is Linked
There were incidents that some folks were trying to make use of internal links to boost PageRank of a page too. But finally get penalized. Just DO IT RIGHT.