https://bits.blogs.nytimes.com/2014/10/31/slack-a-start-up-…

https://bits.blogs.nytimes.com/2014/10/31/slack-a-start-up-with-an-app-to-foster-business-collaboration-is-valued-at-1-1-billion/?searchResultPosition=4&mtrref=www.nytimes.com&gwh=7553F2054215CC72F651284392EA9D00&gwt=pay&assetType=REGIWALL