About two months ago there was a little brouhaha concerning Hulu’s traffic, since the unique visitors reported by comScore were triple Nielsen’s figures. This incident is well analyzed in this posting by Greg Sterling at SearchEngineLand which concludes that “one has to look broadly at all the numbers and use the consensus and directional trends.”

Neither comScore nor Nielsen have issued press releases with new traffic information for Hulu so I’ve compiled charts based on previous releases. Comparing the measurements for visitors over this longer term reveals that the two firms have differed for some time. Nielsen reported 6.32 million unique viewers for Hulu in September 2008, and 10.11 million in May; an increase of 60%. For its part, comScore rerported 25 million viewers in December and 40 million in April; a parallel growth of 60%. Since both firms report very different absolute figures but closely similar growth rates it is more rational to follow Greg Sterling’s afforementioned advice and pay more attention to the similarities and trends between the Nielsen and comScore.

The difference between Nielsen and comScore measurements was much less, looking at the total video streams served per month. Both companies indicate that Hulu has had a steady growth in video streams since its launch in March 2008.

Both Nielsen and comSocre are indicating a strong growth for Hulu in 2009, which can be mostly attributed to the ad campaign launched by the Superbowl spot with Alec Baldwin (inexplicably currently unavailable at Hulu). Given this greater brand awareness it will be very interesting to see how Hulu continues to perform during this summer, especially since it should be a golden opportunity to attract more viewers as the summer TV season has been somewhat slow.