New and existing technologies could affect our ability to customize ads and/or could block ads online, which would harm our business.
Technologies have been developed to make customizable ads more difficult or to block the display of ads altogether and some providers of online services have integrated technologies that could potentially impair the core functionality of third-party digital advertising. Most of our Google revenues are derived from fees paid to us in connection with the display of ads online. As a result, such technologies and tools could adversely affect our operating results.
Google has been telegraphing this for months. Either switch browsers now or enjoy your ads.
They’ve literally said ad blockers are a threat to their revenue https://www.sec.gov/Archives/edgar/data/1652044/000165204419000004/goog10-kq42018.htm