See the little graphic on the bottom of the page that says, SiteMeter? Anybody can click on it. It takes you to a site that tracks visitation stats for this blog. They track several stats, like which URLs you came from (called a referrer), which pages folks visit the most (my post on image grabs from Garmin's is still the top reason folks come here) and where folks go from here. SiteMeter is a free service. Anybody can use it. Even your friend can use it to spy on other folks. Really.
This link shows page recent visits by referral.
Not sure if it matters to any of you, but there's no magic going on. I hope you realize that you're being watched by the web. Not just by your ISP, who knows every site you visit, but also by the very sites your visit. You should assume that all of them know this sort of stuff. If you're particularly paranoid, stop surfing the web now.
Here endeth the lesson.