In Forbes, Eric Goldman writes:
The “Google” trademark regularly ranks as one of the most valuable trademarks in the world. In 2011, Forbes estimated the trademark’s value at $44B, and a more recent estimate placed the value at $113B. Almost certainly, the “Google” trademark is Google’s single most valuable asset. Recently, Google’s opponents in a court case claimed the trademark had become “generic,” so everyone could freely use it without restriction. Fortunately for Google, the court decisively rejected the challenge, confirming that “Google” remains a valid and protectable trademark.
The court summarizes:
The word google has four possible meanings in this case: (1) a trademark designating the Google search engine; (2) a verb referring to the act of searching on the internet using the Google search engine; (3) a verb referring to the act of searching on the internet using any search engine; and (4) a common descriptive term for search engines in general.
The courts say that even if Google’s opponents proved that a majority of consumers understand definition #3 (Google as a verb for Internet searching), Google showed 90%+ of consumers understand definition #1 (Google designates its own search engine), so the term Google still functions as a source designator. As the court concludes, the “undisputed evidence is that the consuming public overwhelmingly understands the word google to identify a particular search engine, not to describe search engines in general.”