Why does Google provide free open DNS servers?

Performance - Google has many services that are used by billions worldwide so they need to control every part of the tech stack to offer the best performance. They're also interested in a fast internet because it encourages more use of their services. read more

If you use Google rather than one of the better alternatives, you’re giving them your entire click-trail, regardless of whether your browser is in “private” mode or you’ve deleted cookies, as well as every other DNS lookup that your machine does, such as those for the software updates of every piece of software on your computer, and every piece of malware as it contacts its C&C. read more

The Domain Name System (DNS) protocol is an important part of the web's infrastructure, serving as the Internet's phone book: every time you visit a website, your computer performs a DNS lookup. Complex pages often require multiple DNS lookups before they start loading, so your computer may be performing hundreds of lookups a day. read more