A Big Data Police State?

If you look at the long term future of social media, I do not believe that privacy is the main concern. It is of course not the best place to share those things you would not want to be public. But the larger part of 'posts' will be hardly compromising for its users.
That is, if taken separately. The long term trend in social media appears to be building search algorithms that can make sense of all these posts, and attach a meaning behind them to individual users. As Facebook developer Rasmussen explains in a BBC-interview about the value of newsfeed posts:

"It's by far our biggest data source. The engineering challenge of building a search index that can manage that volume of data is big. We're well underway to making the system scale that far - we just aren't there yet."
It means a friend searching for "Friends who like football" could identify you if you had once written something like "Come on United!" in your feed.
[...]
"There are really interesting techniques around sentiment analysis," Mr Rasmussen says, "where people try to take text and figure out whether it's someone saying they like something or don't like something.
(See: BBC News - Technology, "Lars Rasmussen: the brains behind Facebook's future")

 A few months ago, when we started an ETFI-project on the future of social media, I spoke of a scenario in which both industries and governments would adopt a more repressive attitude. The fact that social media as Twitter have created temporary openings of free speech in totalitarian countries is a matter of technical unpreparedness rather than a feature which is inherent to the new media. On the contrary: indepth indexing of newsfeed posts will be an unprecedentedly powerful tool for repressive organisations.