A week ago I received an invitation to use a free version of Google Analytics, a visitor tracking website.
I installed it and have been using it for a week, and I really like it. It has a lot more features than most other visitor counting tools, such as the Onestat counter that I also have.
For example, it is possible to define "conversion goals" -- a custom goal that will be tracked by Google Analytics. I added "Posted Comments" as a goal, so now I will have a nice graphic overview of the amount of Comments posted over time.
An interesting piece of information I found is that the most commonly used search-phrase to reach my site was (last week) "how+do+you+pronounce+guus".