For those that have had their website created and designed for them, some form of analytics would have (or should have) come with the site. Analytics is the tool you use to track the traffic that comes to your site. It can provide you with all sorts of interesting information like:
Where your visitor is from
What they typed in to get to your site
What ISP they use
What browser they use
What type of computer they use
How long were they on your site
What did they look at and finally,
When and from what page did they leave.
Now I won't go into how to measure and compare the data on the context of your market, there are plenty of sites that can help you in that regard. But for us specifically I want to stress the importance of regularly checking your analytics so you can identify trends and what to look for.
You should be checking your analytics at least once a month. For labs that are servicing their immediate geographical area only, the more traffic you have coming from outside your target area the more indication that your seo and keywords are too general and you need to include geographical references in your site e.g. Colorado, Aurora, city center, road 70B etc.
But the most important of all the analytics is what term the visitor searched to get to your site. With this information you can see what dentists in your target area are searching for to find you. This information is the best thing you could ask for. It will allow you to contour your site to appeal more to those search terms and give you an indication of the terms your also missing.
If ever you're stuck and don't know what to do, there are thousands of SEO optimization sites that have tips and tricks and consultants ready to help you improve your google rank.
I suppose the summary is don't discount analytics as being a thing of interest. It is a tool that will help you shape your site into what your potential customers are looking for.
Please feel free to add comments, experiences and questions!