Even the examples given by the author were the product of acquisition, including GMail.
Caleb has a point: Cite? Wikipedia (which I admit could be lying because it could have been edited by Google employees) says otherwise. It says the closest thing to an acquisition of GMail is when they bought the existing domain name from Garfield.
Another thing I'll admit is that Gmail wasn't innovation at all, it was merely copying other existing web-based mail services and trying to outdo them by being slightly better. For me, what made me switch to Gmail was the significantly improved spam filtering, nothing more.