Here's a blog post with some background on these servers: http://www.tummy.com/articles/famous-dns-server/
"[...] DNS infrastructure is largely split into two types; open (public) and closed (private). Open DNS is provided by companies like OpenDNS, Google and Level 3. You can use it wherever you are on the Internet with no restrictions or authentication required."
- Mark Taylor, VP at Level3
http://blog.level3.com/level-3-network/a-flawed-study-of-cdn...
I can't find any cite where anyone else who I would consider a reliable source in the DNS world (Vixie, &c) repeat this claim. To the contrary, Level 3 is often grouped with Google, OpenDNS and others in discussions of open public resolvers [1][2][3], and those in the know never seem to speak up and say otherwise in these discussions.
That being said, I have absolutely no personal knowledge on any of this.
[1] http://www.maawg.org/system/files/Fergie_DNS_Open_Resolver_M...
[2] http://markmail.org/message/gh7f2wvfbn5mpvuq
[3] http://www.circleid.com/posts/87143_dns_not_a_guessing_game/...
So no, definitely not altruistic.
"We built Google Public DNS to make the web faster and to retain as little information about usage as we could, while still being able to detect and fix problems. Google Public DNS does not permanently store personally identifiable information."
What is the test for "intended for widespread public use"?
If a server is configured to accept queries from any IP address, can we conclude anything about "intent"?
If the server admin does nothing to stop widespread public use (which is trivial to do of course), can we conclude anything about intent?
Is there some other clue we need to look for?
Under your reasoning, it's "reasonable" to provide open resolvers and hijack NXDOMAIN responses, so long as there is no "intent" for widespread public use.
Interesting.