This has been brought up before, in a different article.
I think the key problem is: who the hell are Hitwise, and why should I believe their metrics? I'd be interested to know where they get their data from.
I don't think anybody can reliably compare websites, unless they run the server. I guarentee you that Hitwise is not counting my hits on Google, and I wouldn't be surprised if they were counting my sister's hits on MySpace. So instantly, the results are skewed.