Wait - what about MS Lync/Office Communicator? I don't remember if that was just a branding change of "MSN Messenger for Business" about the time right before the Skype acquisition, or folding in (and failing with) yet another IM/Video chat solution. So should the count actually be three?
Yeah, it's actually three, though only from a branding perspective. They did rebrand Lync/Office Communicator as "Skype for Business" for a bit, though I don't think there was ever any code shared and it was just a branding thing.
Honestly I think they simply don't care, and from their perspective they finally have gotten it right with Teams.
