… but are you really surprised? This blog post from my provider, easyDNS, explains, very simply, why they are needed:
For the vast minority of domains, we’re talking domains that use tens of millions or hundreds of millions of queries per month (in one case a domain that has been known to hit 1 billion queries per day) – I’m sorry but we have to bring things back into reality. Getting that kind of usage on a DOS fortified, globally deployed anycast DNS network such as ours for $15 or $50 per year was nice while it lasted, but it’s basically costing us money to carry it.
1 Billion DNS queries in one day!