Friday, May 15, 2009

Tracking Hulu's viewership

The NY Times is running a piece on the difficulty of counting the number of unique visitors to streaming video sites, like Hulu. Apparently, Nielsen's estimates of the total viewership for Hulu are far lower than that of other measurement firms.

Nielsen seems to be extending the model they use for tracking TV viewership to online video. In this case, they monitor the online viewing habits of some 200,000 users and weight them to extrapolate the total viewership of the site. This is clearly error-prone and potentially leads to substantial bias in the reported results.

I don't understand why Hulu does not simply track the number of unique users to their site directly, using IP addresses and cookies -- just like most other websites. Hulu should have all of the information it needs at its fingertips; why get Nielsen in the loop? I recognize that tracking IPs and cookies not a perfect approach, but I am surprised that Hulu needs to rely on a third party ratings company for its metrics when there are well-established technical solutions out there. The only guess I have is that it's to ensure that the ratings numbers can be independently verified, but there must be a better way than tracking viewership of a relatively tiny slice of the population. Can someone explain this?


  1. I'm sure Hulu has exact numbers, but independent traffic reporting is very important for advertisers. One of the better ways is through a toolbar, like what ComScore uses, but all of these mechanisms have bias and it can be very easy to miscount. Personally, I think the Nielson method is totally outdated and doesn't even work for regular television.

  2. Yes, I work in this space, and it's all about third party measurement. Nobody cares about Hulu's self reported numbers if they're trying to tell whether the ads they paid for are showing to the right amount of eyeballs. The problem is not a technical one.

  3. That's what I assumed. What's interesting is that the NY Times article never mentioned anything about Hulu's own estimate of their viewership (just estimates from two third-party companies). There must be a good way of generating verifiable host-side usage statistics that doesn't rely on a third party observer.

  4. Here's a straw man approach: have Hulu run a middlebox that uses a trusted platform module to attest to a small piece of software that just does the logging of streams and produces reports signed with a key sealed under the platform configuration registers corresponding to that software. Advertisers can audit the software to make sure it does the right thing, and they can query the middlebox whenever they want to have the TPM attest that the box is running this software.

    Additionally, have Hulu post a bond for $10MM that forfeits to charity if any evidence of physical tampering with the middlebox is found. Have an auditor paid by the advertisers perform random inspections.

    What obstacles stand in the way of doing this?

  5. So the box would have to sit between the user and Hulu servers for every bit of traffic, adding a hop?

    It seems more reasonable for akamai (or any other content distribution network) to build in traffic reporting, and if the site agrees, release those numbers or an estimate using those numbers to determine total traffic.