I don't know the technology, but it isn't your cache or cookies that are the culprit. It is some sort of aplet that is downloaded by the site that then remains resident in your browser. So refreshing and clearing cache and cookies does nothing. I don't know if closing and reopening the browser clears it. Some sites, even with infrequent visits, seem to know what you have been up to. In my opinion, extremely creepy.
Personally, I use anti-tracking software.
But I may be more paranoid than is warranted.
You're not.

We'll be waiting with bait on our breath.

