We have biggest example of such breach from the well known company like Facebook and I am sure that everyone will have the same opinion as of mine. Dont forget that they used our personal data publicly to share with the third parties and this was confirmed by the Mark himself. Not only this I do believe that other companies like Amazon, Twitter, and Google are using our day to day activities to track our movement and know what we like and what we dont like. Depending upon which they do make changes to how the internet looks like to us and thus its kind of use of info itself. But may be no one says anything about it as it comes under user agreement and thus we ourselves giving them permission to use it.