Zynga has been accused by many (and sued by a few) of directly copying certain game design elements. According to Zynga CEO Mark Pincus, the company's philosophy is to mix “proven” features with new elements and won't be defined by what others think about Zynga's practices.
"For us, innovation is about making games more accessible, more social, more fun, and more free — giving you more value for your time and money," Pincus said. "We don't define innovation by whether or not our Words With Friends game looks different enough from Scrabble. We think it's an innovative game because it's connected tens of millions of people together."