Flipping existing concepts upside down

While I was researching existing concepts of most popular apps I realized that most of them took existing concept and flipped it on its head. Maybe I'm wrong for some of them

Snapchat
Existing concept: uploaded images and photos stay online (forever)
Flipped: images and photos stay online shortly

Vine
Existing concept: videos are long
Flipped: videos should be short

Whatsapp
Existing concept: SMS are not free
Flipped: SMS are now free

Twitter
Existing concept: blogs/blogging should have large texts
Flipped: blogs/blogging can be short

Digg
Existing concept: News should be aggregated by journalists
Flipped: news can be aggregated and voted on by visitors

Tinder
Existing concept: dating online is opened for people to send messages to whoever, no matching
Flipped: you need to match in order to continue

These are of course most popular examples. Seems like all of them followed the same formula, probably unintentionally. Of course some of them were lucky, some had good marketing. What's your opinion on it?