Earlier quoted context omitted.
I'm not talking about using just visits to improve search though, I'm talking about using the pattern of interaction on a site to basically replicate a site's data. That is, imagine netflix recommends movie X to you, now Bing infers that Netflix has done so using custom code to parse their IE logs, and then recommend movie X to you. IMHO, this would be completely unethical. That's exactly what Bing has admitted to do…
I'm not sure I get your example (not clear when Bing would recommend a movie to me). So let me give that I do understand. I go to Netflix and search for the move "Network". I end up clicking on "The Social Network". Later on Bing, if I search for "movie Network" -- I'd hope that one of the movies that comes back is "The Social Network", based on that clickthrough data from Netflix.. In my mind the only thing that is…
Now bing implements a movie recommendation service, which also magically recommends for you "Social Network", based on clicktracking of Netflix.
IMHO, what Bing is doing with Google is exactly the same scenario as above (extract click data from a competitor's service, and surface the exact same data in their own product).