I'd say Slack has better penetration into enterprise than all those except sykpe. if you look at Amazon's prior communication attempt, its aimed as a business c

I'd say Slack has better penetration into enterprise than all those except sykpe. if you look at Amazon's prior communication attempt, its aimed as a business communication solution. Slack has done well to penetrate that segment. Your list is consumer grade, whereas Slack, Webex, Gotomeeting, Zoom, bluejeans, google meetings etc are focused on improving business communications.