It's a relatively simple question whether a certain trait can be 'ascertained' by these systems, and to what accuracy, in a given context. There are a number N

It's a relatively simple question whether a certain trait can be 'ascertained' by these systems, and to what accuracy, in a given context. There are a number NLP programs that can detect a writers gender from text at a much greater accuracy than raw chance, especially in a limited domain. The problem is that the world is a big, messy domain. There's no reason in principal that other traits wouldn't be 'detectable' (although I doubt sexuality), but the problem is getting a good set of training/test data in context, and what your acceptable threshold for accuracy is. I'd be willing to bet that people whose text messages contain lots of U's and L8R's probably have worse credit than those who text in proper English, but there are much better ways of doing a credit check. If that's only accurate to, say, 100 FICA score points it's probably not worth using it. I wouldn't be too worried about big brother(s) using semantic analysis to read your mind, but don't discredit the fact that language patterns encode certain cultural information that is identifiable, or at least correlated with behavior.