Deface Page Say's:
DNS spoofing (or DNS cache poisoning) is a computer hacking attack, whereby data is introduced into a Domain Name System (DNS) name server's cache database, causing the name server to return an incorrect IP address, diverting traffic to another computer (often the attacker's).
Every country have registrar server which return the IP of local huge sites like google, msn etc. If registrar sever is compromised then we can redirect all those domains to specific ip which make it believe that sites are hacked. Basically sites are functioning properly, only there ip is hacked to hacked ip.