I just saw this comment on Hacking Netflix:

What I REALLY want to know (And don't think anyone at Netflix would answer me on) is what "Flagging a Review" actually does. When I flag reviews, I do it because they are either not a review, they posted a url in the review, etc. Am I wasting my time by flagging them, or does Netflix really go through and look at flagged reviews to find the junk?

Does anyone know, or is it a big company secret? Now that I've got that email address, I might use it, but I wonder if flagging does the same thing.

First of all, why don't you think anyone at Netflix would answer this? Have I made it appear this is a big company secret? I thought i had explained this in the past, but i'll take a new stab at it here:

The flags are methods for you, the Netflix members, to self-police the reviews on the site. They are automated. We spot check them, but we have tuned (and continue to refine) the automated process triggered by flagging a review.

The short answer is that if a review gets a quantity of flags from different members, we move the review off the movie display page. It is not removed from the site, and will remain among the reviewers other reviews on their Profile pages. The algorithm that does this removing is the thing we keep refining. It would be too simple to say it takes X flags to get something pulled. It depends on a few factors, but particularly the helpful/unhelpful votes. If a movie has a quantity of helpful votes, for instance, it takes more flags to remove it. (We don't want the flags being used to remove reviews that are simply controversial, or irksome to a small group.) We also want to give new reviews a little bit of time to get seen, so on popular titles that period might be less than for smaller titles... but either way, it is automated, and really is working. Over the past few months we've changed the thresholds and we continue to find cases where folks are misusing the system and thus we revise the algorithm to account for this. The thresholds and algos are also different for "this is not a review" and "objectionable content" (etc) and we know some people who don't like a review just click on everything hoping this will accelerate the removal (it doesn't). I presume we will continue with internal tweaks to improve it over time.

There. Secret is out of the bag.