The same reasoning can be applied for Twitter. However the technological breakthroughs needed for such a system is still not in place. Facebook/Twitter has to

The same reasoning can be applied for Twitter. However the technological breakthroughs needed for such a system is still not in place. Facebook/Twitter has to put in a log of research into Natural Language Processing Technologies for this scenario to materialize. The cost of that is still unaccounted for. However the value of correct data is very important here. No doubt the data Facebook has about its users is very valuable. Especially considering the fact that there is a real person on the other end, with a significant amount of real life relationship amongst his/her friends list. Someone still needs to figure out how can that data be converted into dollars.