[ssivark]

Well, apart from Amazon to some extent (we'll find out in twenty years), none of the others have fundamentally altered our lifestyles. Eg: Google -- searching the interwebs is a crazy fantastic capability... But most people aren't really using to live their lives any differently from twenty years ago.

I think YouTube (and possibly Facebook) might be among the only other web services having significant qualitative impact on people's lives. Maybe Uber/Lyft for an American audience used to owning cars.