> There were three main challenges. First, PowerDNS when under large in-bound DDoS loads would consume excessive resources and occasionally fall over. Second, and more insidious, because the version of PowerDNS we were using did not have abuse detection and rate limiting, we were increasingly seeing attempts at using CloudFlare authoritative DNS network to launch reflection attacks against others. And, third, it was very difficult to extend PowerDNS and add any sort of application logic which kept us from doing interesting things... like adding Easter Eggs.

Source (was linked in article): http://blog.cloudflare.com/the-story-of-a-little-dns-easter-...