When was the last time that you checked your site's web statistics? The web stats report can provide a lot of valuable information about the performance of your site, but I find that most people rarely look at them. Your web stats gives you an overview of how many visitors are coming to your site, what pages are the most popular, what websites are linked to you, and even what keywords people have typed into a search engine.
You may find some surprising things. A client that I took on already had an established site for his business. I didn't expect to find much traffic. I was shocked at the web statistics I saw -- tens of thousands of hits a month. You see, totally unrelated to that business, he had set up a page with photos of a classic Ford Mustang that he had restored. And true to the nature of the internet, a few folks had found the pictures and displayed them on their site by copying the link (rather than the photo). That exposed the photos to more people who, in turn, copied the link rather than the photo, and so on, and so on. Those photos were EVERYWHERE on the internet, and all of these sites linked back to the originals on my client's web server. We could have simply taken the photos down and been done with it; instead, I suggested pulling the images into Photoshop and typing his business's domain name into the bottom corner of each one. I resaved them, and we instantly had a marketing campaign reaching tens of thousands of people at no cost.
Obviously, that's not a typical scenario that most people are going to find themselves in. But, it does illustrate how valuable the web stats are in helping you to monitor how the real world is interacting with your site. It also helps you to measure the effectiveness of the content of your site, and to rework that content until it achieves your goals.
For example, looking at your keywords may help to guide you in redrafting some of your web pages. The keywords are directly linked to the content of your site. If you see that the wrong keywords are being used to find you, then you might want to consider rewriting some of your pages to increase the number of keywords that you do want people to use to find you.
I suggest that you check your web statistics at least once a month, and make adjustments to your pages accordingly.