You can only post once every 40 minutes.
I got this response from bitcoin forum while trying to ask a question, strangely I had not asked anything in last 40 minutes, In fact, that was my first question in the forum. I assumed someone from my IP, Perhaps my office might have asked a question in the same period. As I checked the newest questions in the forum there had been only one question for 40 minutes, It was by a user who has not revealed his identity. But now I have a clue about his IP and I went through the questions from his other SO profiles. Apparently, he is from my office. I did not try further to establish this fact. However, is this not a privacy breach?