It can be in your interests for businesses to know things about you. However it is always in your interests for you to be in control of your own personal data a

It can be in your interests for businesses to know things about you. However it is always in your interests for you to be in control of your own personal data and how it is used, which is not how Facebook operates. Whether or not FB as a platform is useful is irrelevant to the issue of data ownership. Where people have a particular issue with FB, it is, ignoring Mark Zuckerberg's own statements, that as a business they are reliant on what you might call adversarial data collection: i.e., they will take whatever they can get, not just what you explicitly give them. Contrast that with say, Google, who have been heading in a similar direction for a while now, but they don't predicate their entire business model on it. If Google stopped collecting your data today they would still have a very viable business selling advertising based on search terms. If FB stopped collecting data, the company would shut down. Thus any utility you get from Facebook is being paid for by a specific model of data collection that happens to be contrary to your best interests. You might be happy with that trade-off but a lot of people aren't. I for one an unhappy with the fact they have become a defacto standard that's getting increasingly difficult to avoid.