Ask HN: What happens if Google's Public DNS fails? 8.8.8.8 8.8.4.4
I know that Google has probably the best servers in the world. But seeing how many people and companies (even seen it on telecommunication companies) rely on it is frightening.
I guess the predictable would happen. Badly configured systems would stop working. Systems with a working secondary DNS would keep working.
More interesting question is what could you do if 8.8.8.8 was compromised? That could be interesting.
I do agree that such block is enough to deter most non-technical users.
I use both G and ODNS - when the local defaults aren't working. I definitely would not recommend these as your primary servers, precisely because they're provided merely as a courtesy to you, without any guarantees whatsoever.
So this is not a problem really.