On the morning of 27 January 2014, AT&T UVerse services appear to be suffering from DNS problems. A graph from Down Detector suggests that the problem is widespread. The observation is that some sites will load but others won't (like Hulu, New Yorker, Reddit.)
One of the suggestions given was to switch your DNS from the AT&T provided service to a third party, such as Google (220.127.116.11). On my Mac, go to System Preferences > Network > Advanced ... > DNS and change the DNS server address.