When I read the book a few years ago, the most striking thing was that the names Archer Daniels Midland and Dwayne Andreas didn't appear on the cover or liner notes, and I actually had to look pretty deep in the book to figure out what company he worked for.

Now that ADM pleaded guilty and paid a $100 million fine, their lawyers have less to work with, but at the time the publisher was apparently pretty scared of them. The book is also exceedingly careful about alleging that the Andreases knew how their company did business.

http://www.netflixprize.com/community/viewtopic.php?id=1498

"Thanks. In fact, this is a very happy day for us - our team is top contender for winning the Grand Prize, as we have a better Test score than The Ensemble. (Probably this is the first post revealing this in the forum smile)"

Also, Yehuda Koren is at Yahoo now, not AT&T.

I don't think this is quite clear. The teams submit their predictions on a qualifying set of about 1.8 million user/movie pairs. Half of these are used for the published leaderboard rankings, and the other half secretly scored for the actual prize. What the teams don't know is which user/movie ratings are in which half. The teams aren't submitting programs that Netflix runs though, they're submitting predictions on the whole quiz set.

In fact, according to the second post by Yehuda Koren in this thread, it looks like BelKor does have the best test error rate and will be declared the winner. http://www.netflixprize.com/community/viewtopic.php?id=1498