This was released by Yahoo! at Shop.org:
Back in December, I tried to compare apples to apples and highlight unique user data for all of the shopping comparison engines. Unfortunately, not all the engines were interested in releasing the information AND the audience measurement data from comScore, NetRatings, and Hitwise was a bit messy. I’ll try to figure out a workaround, but in the meantime, I wanted to at least push some of this information out there.
What’s interesting about Yahoo! Shopping’s traffic data is that Cyber Monday actually lived up to the hype. Most comparison engines I talked with leading up to the holidays said that traffic usually spikes around the second Monday in December.