Some error corrections: ebay bought skype in 2005 for 2.6B (1 million concurrent user), and Microsoft bought them in 2011 for 8.5B (22 million concurrent users) with 74 million concurrent users reported in 2013 falling to apparently 30 million now...
https://www.statista.com/chart/1417/skype-usage/
What is your criteria for stewardship ?