Something else to consider -- being sidebar "Popular" probably has some level of "self-fulfilling prophecy" to it.

When a First Timer arrives to see Today's Article for whatever reason, there's probably a good percentage of Read A Few Populars being done by that First Timer on that visit. I'm pretty sure that's how my own First Visit went, and I spent a few days reading older stuff, liking it, and thus it earning your spot on my feedreader.