How Amazon, Apple, Facebook, and Google have used extensive acquisitions to expand into new areas, creating new revenue streams and outflanking competitors (Washington Post)

Washington Post:
How Amazon, Apple, Facebook, and Google have used extensive acquisitions to expand into new areas, creating new revenue streams and outflanking competitors  —  You're probably reading this on a browser built by Apple or Google.  If you're on a smartphone, it's almost certain those two companies built the operating system.