Zynga was ripping off games that were popular in places like china, they had zero innovation, not even in their slimy tactics to recruit users. They used to have those "invite 10 friends to be able to play" that everyone had back then. they abused every possible channel to the maximum degree, that's their only 'innovation'. They were the reason that facebook created rules that ban those shady tactics, even though they had a special agreement with facebook (basically so they can spam more than indies and competitors). And a lot of more shady antics i can't even remember, they were all discussed in facebook's old developer forum which has been shut down long ago.
Zynga was not "the first" in anything