I'm fascinated with Google Trends. It allows you to compare public interest in specific topics over time, as expressed in web searches, I do bizarre comparisons just for fun. Recently I compared interest in the Mississippi senatorial candidate Chris McDaniel, with Kris Kringle. The results of that search probably aren't meaningful, but it's fun to dig down into the specifics, particularly if the graph has spikes during certain months.
This comparison turned up something interesting. There is more general interest in Karl Marx than in Groucho Marx, but the popularity of Karl Marx as a search subject fluctuates on a somewhat even and regular basis. Why is this? Does the interest in Marx go up at some particular time of year? I don't know if I'll ever figure it out, but here's the chart. If you have any idea why the regular pattern in searches on Karl Marx happens, please comment on it.
If you want more detailed information on the results, including the geographical breakdown, just click on the Google Trends link below the graph.