There is a big difference between being able to analyse your meta data, thereby getting to know a great deal about your personal preference on STEEM, as opposed to having that information available on a platform that can target you with tailored advertisement. It may become an issue in the future, however it is not at the moment in my opinion.

The blockchain, in time, will probably provide the originator of meta data more control over what is to be made public or not. Such evolutionary change will, likely, be user driven.