In regard to the Hitwise data showing MySpace drives more retail traffic than MSN:
MySpace has made its way into the mainstream, agreed, however it can not be the banner ads/links that are driving retail traffic — the ads on the site are rarely for the aforementioned product/retail sites. A more likely conclusion would be that visitors are stopping in to check their MySpace account the way older web users read the news and then venture on to their next site. If Date.com or “Shoot the Duck & Win a Free Ringtone!” sites saw huge increases in traffic we could say it’s the banners, but…
Additionally, MySpace prohibits non-paid advertisement links on the site – so profiles aren’t necessarily allowed (but are sometimes permitted) to link to other sites from their homepage.
Note: this was cross posted from my comment on their site.