The policy that Mozilla ask providers to follow does not prohibit data-mining the traffic. Providers are requested to not store or share personal information, but any data-mining that removes personal identifiable information are allowed.

For example, accidentally leaked internal network queries from companies are up to grabs. As is market data like what people are querying, how much, when, from where (geographical for example) and to whom, and so on.

The quality of the anonymization of private information are also not guarantied.