I monitor my website's traffic using WebSideStory and IndexTools.com. I don't do this in a big brother sort of way, but just to see where people are coming from and how they spend their time on the site. I want to see where people are coming from so I can see if the time I spend promoting my site is worthwhile. I can also see what people are looking for and target Memorize-It accordingly. Recently I have been watching our new Flashcards site and noticed that most people were only looking at the card categories and not the more detailed information on each deck. I went back and looked and the card category page did not clearly show that there was more information on each deck. I added the text "More Info..." to the link. Over the next few weeks I'll keep an eye out to see if this generates more traffic to the actual decks.
That said, if you are running a website, I highly recommend doing analysis on your website traffic. The two I recommend are WebSideStory and IndexTools.com listed on my WoodsGoods.com site. It is nice to know when and if all the work you are doing is worthwhile. In my case I can see more about what people are looking for in Memorize-It and make the software better for everyone.