Very pitifully few of Google's projects have either created new markets they can dominate, or have penetrated existing markets to the point they can drive billion dollar business units. Gmail, Maps and Android exception to that point, but Google is woefully incompetent in most other respects. And the first two in that list are simply different takes on the search paradigm while Android is a knock-off of the iPhone OS (a really good knock-off, but certainly not a game changing original new idea).
Those are very big exceptions.
I've not seen that many software products which were so obviously disruptive; it's no wonder they became giant-killers. Facebook is the only other one I can think of.
On the other hand, some of their other big products have not be a huge success precisely they haven't been game-changers. Google Docs, for example, might be a good example of a web office suite; but it's hardly a game changer as far as office suites go, because it doesn't do some of the core things that people do daily with office suites. It was clear from the beginning that it would be a slow starter. Whereas Maps for example, you knew at the beiginning that nothing else could touch it