I collected snapshots of the reddit homepage every 5 minutes over a period of about 10 hours starting at around 10pm Eastern on August 6th, and this shows how pages travel down as time passes. A bar at the nth position with number i indicates that, at the time shown, that url was displayed at position n and started out at position i. Bars of this color represent pages that weren't initially present on the homepage.
You can start the animation by clicking Start or step through individual snapshots by clicking Step. Hovering over the individual bars will show the URL for that position, and clicking on it with open it. I couldn't find a better way to display the URLs, and really, they don't matter.