We will focus in this paper on how social media, in particular Twitter, were used to trigger, propagate then regulate social controversies in a way that challenged real-world knowledge about the person concerned. We have chosen as case study, the controversy surrounding the beleaguered Nobel Prize winner Sir Tim Hunt whose lifelong career was destroyed within a few days due to a social media campaign following a speech he gave on the 8^th of June 2015 during a lunch with women scientists and journalists in South Korea.

This controversy illustrates challenges posed by social media for knowledge acquisition and organisation in the 21^st century. It appears that knowledge and truth will depend not so much on who you are in real life and your ability to put forward verifiable facts but on your social media network and activism in the virtual world. There is a very real possibility that the truth-value of socially-constructed KOs will be highly questionable and unverifiable with the traditional top-down approaches based on authoritative sources and will call for designing more adaptable and flexible modalities for designing KOS involving humans and machines working in real time