This document discusses how some companies have reduced internal email usage by adopting enterprise social networks (ESNs). Atos saw earnings per share increase by over 50% and administrative costs drop after moving communications to an ESN. Intellect Design Arena saw project development time reduced by 12% and freed up 1.3 million hours per year towards productive work after implementing its ESN called Unmail. Microsoft also uses internal collaboration tools and cites examples like Bajaj Finance improving its marketing strategy based on employee interactions on the platform. While internal email can't be completely replaced, ESNs allow for improved information sharing, collaboration and productivity when used alongside existing email systems.