It seems to be localized with the Comcast network, but of course this is effecting a large audience, since Comcast is a major ISP.
I have a support ticket into enom.com and have put in a higher level support ticket to Comcast. Comcast said it would be 24 to 72 hours to resolve.
Note that if you have a domain at enom.com that uses other nameservers you are fine, its just their dedicated dynamic DNS (or bulkregisters).
dns1.name-services.com
dns2.name-services.com
dns3.name-services.com
dns4.name-services.com
dns5.name-services.com
Let's see how it resolves...
It is definitely an issue with enom.com and Comcast not playing well with each other.
We added in two entries to point to our managed server at Rackspace and our domain started working on Comcast within about 30 minutes.