Nonsense, just because they used ensemble approaches doesn’t make the algorithms impractical. Ensembles have been seen to do well in many machine learning problems in the last decade.

The leaders submitted multiple times in the last hours of the contest, which suggests that their algorithms run in a few hours, at most. How often does Netscape have to recompute recommendations for a subscriber, every day, perhaps? This seems eminently possible.

The problem with the winning solution(s) is that they are not practical and will not be used in real life.
The conclusion from the Netflix prize is that no team was able to develop one “super algorithm” that improves Netflix’s by 10%.
Eventually many teams had to join forces and combine as many algorithms as possible to create a clumsy solution that will not be practical in real-time environments.
I believe that the real solution will come from companies like ours – BeeTV (www.bee.tv) or our competitors, companies that are focused not only on a mathematical answer but are researching and developing solutions that are looking at the whole picture of pushing content (not only movies!) to humans.