DNS issues are something that isn’t discussed widely, but when they affect you – you’ll know it. When your browser says “Looking up www.xxx.xxx…” and then says it can’t find anything – the reason is generally because your DNS servers provided by the ISP aren’t responding quickly enough.
Comcast has had troubles with their DNS servers off and on, as well as AT&T – and once it happened to me with my BellSouth (now AT&T) DSL – I was freaking out.
That is when I learned about OpenDNS. It’s a public project that is FREE and provides you with a super fast DNS service as well as other great features – especially for families. You are able to block certain website categories, suspected phishing sites and much more – and it is all done by people. People utilize OpenDNS tools to assist in the categorization and tagging of domains so that the consensus answer is utilized to protect others as appropriate.