Blog Traffic Apples and Oranges

Prof. Glenn and Prof. Bainbridge point to a downright interesting report on CNN Money regarding blog traffic.
Allen Wastler provides a chart, apparently using data from comScore Networks, which provides the following trafic statistics for “number of daily visitors” for various blogs on Election Day:
Blogspot.com: 333,000
Typepad.com: 95,000
DailyKos: 86,000
Wonkette: 31,000
A few observations:
From their methodology page, I gather that comScore is coming up with their figures by using a panel of web users and surveying their surfing habits, then extrapolating that behavior to the web universe as a whole.
So, first, we should recognize that their number will not necessarily sync directly with SiteMeter Average Daily Visits, which is our usual metric of choice around these parts.
Second, given their methodology, I suspect that what comScore is reporting is not the total number of visits per day, but the number of unique visitors. Taken in that light, the idea that Kos had 86,000 people who checked his blog throughout the day doesn’t seem too far off base. Since his average daily visits count was around 600,000 at that time, each person would need to check seven times during the day for his total daily visits to amount to 600,000. For a major news day like election day, that doesn’t sound like an unreasonable rate.
At any rate, I have no way of verifying whether comScore’s data is accurate or complete bunk. But, I think we should be careful in comparing comScore’s apples to SiteMeter’s oranges…