This site does something weird, I haven't seen before. As you scroll around the page, not clicking on anything, it adds entries to your stack of visited pages! You then have to hit the back-button N times to get out. It's stealthily redirecting to itself or something like that.

You can monitor this: stay on the page, and then every once in a while right click on the back-button in Firefox (or however it's done in your browser to pop up the forward/back list). See the growing number of repetitions of the page title in the list.