It is not surprise that social media sites have been playing around with big data. What gets a lot of people is, just how personal this information can get.
Imagine joining a dating site that uses big data to determine what you are probably lying about, along with everyone else and then using the data to find you a better match. Or social media can determine if you actually have real friends that meet offline or just chat about sports online.
I am a huge fan of big data, when used properly. But as anyone, there are some things that I am not interested in seeing big data be used for. As long as people have the right to manage their data, then it is ok. But when data is basically taken, that can be a problem.