Stackoverflow reputation problem

Some time ago i wrote gist which described how to install ghc from source on ubuntu. Today i see question on stackoverflow.com connected with my gist. I have fixed gist immediately and think about leaving comment to person who had some difficulties with it. I log on using google account and try to leave comment and … i cant do it because my repuration is too low (this is just new account). What ?!? This is service for questions and answers, why i have such strange limitation connected with main purpose of this resource. Completely disappointed.