Google effort to speed up the web Google now includes its own Public DNS as an alternative to ISP provided servers.
The service follows the DNS Standards set forth by the Internet community and is not intended to compete with OpenDNS which provides filtering and many other features, but also redirects typos to ad sponsored pages. Actually Google joins the ranks of DNS providers such as Level 3 that provide public DNS access.
As stated by Prem Ramaswami
Google Public DNS follows the DNS Standards set forth by the Internet
community which means we do not block, filter, or redirect DNS responses.
These actions most probably belong on the client side rather than the
Google Public DNS IPs