Another fun one was the Netflix Prize, where Netflix published an anonymized dataset, but some researchers at UT Austin were able to de-identify many/most of the users in the dataset by linking them to IMDB profiles based on preferences.
https://scholar.google.com/citations?view_op=view_citation&h...
https://systems.cs.columbia.edu/private-systems-class/papers...
many I would have been fine with. most? no way.