Yet RCP conveniently leaves this out if their average. In 2008 it was included.
One day last week when Rasmussen had Romney up five and Gallup had him up six, RCP included the Zogby poll that had Romney down three, a poll they had not included all year (and haven't included since). The reason might be bias, but it might also be simply they want to keep the race within a one point margin so people keep coming back and checking throughout the day (increasing their ad revenue). I've noticed when Romney hit's 1% over Obama in the average, they start throwing in "fishy" polls to bring the average back down.