To be honest I had the same problem, but did eventually scroll. I think my initial hesitation to scroll was because the top of the page looked so much like it could be an entire landing page, with prominent twitter, facebook, and email links. Of course (now?) there's also a little popup that says scroll, which if clicked scrolls you to the beginning of Ben walking.

I saw the scrollbar, and the little hint saying scroll at the bottom of the page. However, using either the page down key or clicking in the scrollbar confused it. It only worked for me if I scrolled down with the down arrow key and I got to see the speech bubbles that didn't trigger the first time.