It must be noted that they are not taking their actual website or DNS service (as pointed by mintplant below) down. They are censoring some content on OpenDNS g

It must be noted that they are not taking their actual website or DNS service (as pointed by mintplant below) down. They are censoring some content on OpenDNS guide pages which are shown to people who type an incorrect domain etc. to show them the next plausible step in their search.