There is many different ways of stopping data aggregation.
Using a Steem/Hive model that rewards people for creating obfuscation and fake data in large quantities is one way. Provable fake data generation(think provable output, taking in real data and changing it just slightly to make it fake, and doing it 100s of times it is obfuscated), mass sign up of social media with garbage info, anonymizing everything, private and encrypted transactions/messaging/emails/everything, even making software for nodes that encrypt and anonymize traffic.
Depending on how far down you want to go into something like that, a lot can be done.