I've heard reactions to the Cambridge Analytica/Facebook scandal from liberals and conservatives but I'm curious what libertarians think about it. How do you feel about the scandal and data privacy more generally?

EDIT: It seems like a lot of people don't know the details of the CA scandal, and thus why it is a "scandal". The general opinion expressed here is that people whose data were used do not have the right to be upset because they willfully gave their data to Facebook and CA. I think this is fair would be fair if this is all that happened, but this reaction doesn't seem to account for the whole story.

In reality, CA obtained the data in breach of Facebook terms (and I think this might be illegal). Basically, CA purchased the data from someone else who was not allowed to sell it to them. The person they purchased it from was a professor, and bought it as an academic, giving him a much lower rate than a commercial data purchase (which CA should have paid).

Another layer of this is whose data was obtained. Some of the data sold to CA was obtained from the use of an app. You may think "well, people willfully used this app, so they can't be angry". BUT using the data from the app, CA also got data from about 50,000,000 million people who DID NOT use the app or agree to have their data stolen.

So, CA obtained data outside of facebooks terms, and thus outside of what users agreed to. Moreover, data was obtained indirectly from people who did not agree to having it taken.