Big shocker, albeit this is fairly mildly exaggerated.
What it appears to me that comScore measured was the frequency they see users on their properties. Does Yahoo! really get interesting data from people refreshing their mail again? MySpace “has the opportunity to gather” a lot of data, but does refreshing your page every 60 seconds for 3 hours really mean a lot?
They bash Conde Nast for not gathering a lot of data, but the chances they have to gather data are probably far more contextually interesting than basically anything that anyone does on MySpace.
In fact, I would contend that a big driver of the Beacon program that Facebook introduced was an attempt by Facebook to acquire information that was actually valuable from a targeting perspective.
Yahoo can tell that I am extremely interested (high frequency) in emails my wife sends me (granularity). Good luck selling that data.