A few readers reported that at there is trouble on the worldnic.com DNS servers.

Those servers are operated by Network Solutions and are hosting a number of their customer's DNS needs.
Network Solutions was aware of the problem, had a note on their help pages and seems to have fixed it in the mean time.

To clarify the impact to the casual reader:

• Not all customers of Network Solutions were affected.
• No root or TLD servers are known to reside on these machines.
• It's "just" individual domains that were affected, but there might be a lot of them.
  
• Only domains that have all their namervers on these machines will have had significant impact.
  

There is a lesson to learn for those affected and for those designing solutions. Do not put all your DNS servers on the same hardware, the same connections, the same location, ... , the same management. Diversity is the key to success when it comes to the availablity of DNS services.

This might have been very bad news for those organisations wanting to profit from Cyber Monday, the biggest on-line purchase day according to CNN.