One of the more puzzling things to find out is how people measure the size of their audience. I know it isn’t the most exact science, but there can be so many different methods that vary considerably. Looking at our own site, we see wildly varying numbers coming from Comscore, Nielsen, IVW, Google Analytics and our own metrics. Don’t get me started on Alexa, which I find woefully inaccurate, but unfortunately it’s the only free option. That then is a problem with the panel based system of audience measurement, how good a sample is the panel of the general internet audience.