Who was talking about "business use"? I don't think that had been mentioned until you brought it up.
Facebook is a multibillion dollar corporation yet the communications aspect of the website for the so called 'end users' is apparently free. From the business aspect of the Facebook, i.e. the business model, Facebook is a data mining and personal profiling operation which sells on your implied personal information to others. That is the basis for its income stream, although I'm still at a loss at the size of the market capitalisation for the company considering the limited value of the information it generates for purely 3rd party marketeers, which is why there is a suspicion that the News Onion Youtube video is nearer the mark than you would ever suspect.
Facebook et al are also treated by other businesses as a major security threat to their operations, such gathering insider information and industrial espionage.
As you may have guessed already I'm not a fan. What is quite shocking is also finding out about Mickey Mouse's operations also collecting biometric information from its customers. The
All seeing eye it appears is almost everywhere.
There is an ongoing telephone and computer hacking scandal which has polluted the political process and even corrupted the police force at the highest levels in the UK. News international once owned Myspace. It would be interesting to know publicly if any Myspace account passwords were passed to the phone and computer hackers working for another subsidiary within the News Corporation media empire. It might have been a good idea to ensure that personal email and Myspace accounts had separate passwords when this criminality was taking place.
As there is no personal data protection legislation in the US this would be a moot point though as incorporated businesses it would appear don't have any morals when it comes to infringing on personal data protection of individuals.