If you surf this website, you'll find that it's not very interactive. We don't ask for your name or email address. We don't care where you live. If you try to Contact Us, we'll ask for your name and email so we can reply to your questions, comments or suggestions, but that's the only thing it's used for. And when we've replied, we'll usually just delete the message and move on with our day. In some cases, we might put it in our archive folder if we might want to refer to it again later, but that doesn't happen very often.
Our web server does, however, collect information about the browser you use, operating system, your IP address, and such. It's collected into various statistics. It's helpful to know, for instance, how many people are viewing our site on mobile devices to know how much effort we should put into a mobile-friendly version of this site. It's helpful to know what browsers people are using so we know what sort of browers we need to support (or stop supporting). We occasionally look at that stuff, but not really all that often. And by the time we do look at it, it's all grouped with a bunch of other visitors information and there's nothing left to identify you specifically.
You'll also find that our website will put cookies on your browser so we can track your visit from page to page throughout the website. We don't really do anything with this information except if you use that Contact Us page—the cookie lets us know you've submitted information and takes you to another page that lets you know we've received it. (Or at least that the information was sent to us.) Without the cookie, we wouldn't be able to track if you've passed the math problem—i.e. 'human test.' (A typical spambot isn't programmed to answer even the easiest of math problems correctly.)
We also display ads from Amazon.com. I have absolutely no doubt that Amazon.com will do the same thing and place cookies or web beacons on your browser to track as much information as they can about you, although I didn't see anything in their terms of service saying I had to tell you that. =)
That is all! Live long and prosper!