In 2011, the CEO of Atos, Thierry Breton, announced an unprecedented move for Atos. The global information services giant become a “zero” email company with the objective of eradicating internal e-mail use and replacing it with blueKiwi – enterprise social network software. This case serves to teach the challenges and key lessons behind the social collaboration transformation in a large organisation where 76,000 employees switched to a new mode of collaboration. The approach of how to become a “zero” email company is detailed, highlighting the importance of the first-order and second-order change. The case helps to understand what it takes to shift organisational culture and employee mindset, as well as what challenges and barriers need to be overcome to make such an important step on a large organisational scale.