* For the longest time we mostly stuck to doing the math. We certainly didn't call for the contest to be cancelled, and we had nothing to do with the lawsuit. But when some people implied that we were responsible for the mess that ensued, we were kind of pulled into it. We posted this as a way of explaining our point of view and reaching out to see if there's a possibility of collaboration.
* The sadness we expressed is genuine. The reason we brought up Netflix's response to our paper wasn't "snark" or "gloating." Rather, we were pointing out that the cancellation of this contest was rather needless, because if they had acknowledged the privacy risks back when we published the paper, they would have had more than enough time to deploy an opt-in system for this contest. I think it is really unfortunate that that didn't happen.
* Someone wanted to know exactly what I thought of the "greater good" argument. Well, I'll tell ya. I'm vehemently opposed to it and I think it's a dangerous slippery slope. I think this point of view is enshrined in the ethos of this country -- "better let ten guilty men walk free than to convict one innocent man," etc. I don't think anyone has the moral authority to decide that the privacy concerns of a few can be sacrificed.
* There is a specific reason we chose the open letter format rather than communicating with Netflix directly. Acutally, two reasons. First, there are many data privacy researchers who are at least as qualified as we are for this role. We wanted to make sure the community had the opportunity to participate in whatever ensures, rather than just us.
Second, I'm sure there are many companies other than Netflix who have a similar need for privacy preserving data mining. If Netflix doesn't take us up, perhaps one of the others will. Bottom line, since there are multiple parties on both sides, and we don't really know who they are, we felt it is better to have this dialog in public.
* Finally, it is understandable when something like this happens to want to find someone to blame. But think twice before shooting the messenger.