Data privacy seems to be a big issue...but I would think that most user behavioral data can be anonymized and released for researchers, etc to work with. Why isn't this the case?
Is it just really hard to anonymize data (https://www.cs.utexas.edu/~shmat/shmat_oak08netflix.pdf), or is the issue more complex than anonymizing a dataset, or just the lack of an incentive to release data?