Writing style and unique patterns (like time of posting, argument frequency, ideology affiliation, and so on) are some of the things that could reveal someone’s identity and result in actions taken against him.
It happened to me and a friend, who too is in the IT and we go to great length to be anonymous. If something is possible to such a degree, it ought to happen. If it happened to us, it surely happens to somebody else too, especially considering that most people are not too concerned about hiding their trails.
The question isn't whether it's possible, the question is whether it actually happens.