After reading about the dangers of algorithms and the tendency for social networks to collect our information, I am curious why there isn’t a popular social networking site devoted to keeping user habits private? While Mozilla has filled this need with browsers, DuckDuckGo has done this with search engines, and there are countless linux operating systems devoted to this issue, I have not heard of any social networks with privacy as emphasis. With all of the public uproar over the use of private information by Facebook, I would imagine that someone would have developed a viable alternative.
Of course, I am sure there are plenty of reasons why people haven’t done this. For example, it may be too costly or people may not have shown much willingness to actually change their online habits. In addition, it may be that people who want to post information about themselves online are not overly concerned with privacy. Finally, there actually might already be a viable alternative out there that I have simply not heard of or that has been muscled out of the market by larger companies.
What are your thoughts on this? Are there good alternatives? What other barriers are there for new social networking sites entering the market?

Where is the online equivalent to this?