The simple act of visiting a website leaves a trail of information, a “digital footprint,” about visitors like you. Sometimes this footprint is vague and preserves your anonymity and other times it is tied specifically to you and your real life identity.
If all you do is click around and read pages, the data captured about you is vague. If you leave a comment or sign up for a newsletter, the data captured about you is sometimes very specific. Almost all web sites on the web today collect data in this fashion about visitors, and this site is no different.