I think GP meant "product" in a What'sApp\Facebook\Instagram sense of the word. These all (as far as I recall) sort of spread without big "this is gonna change everything" hype\announcements (up to a certain point, I've no idea what that point was - something between ten and a hundred million users?), they just started getting used by people because they were fun and engaging.
The iPhone might be the exception that proves the rule. The original iPod was OS X only, didn't have as much space as a nomad, etc. But people used it organically and pretty soon it took over.
The iPhone would probably have been Samsung's instead of Apple's without the whole iPod/iTunes/Movies business.