I just read about this in the local newspaper.  
They said that MCI/Worldcom accounts for 50%(!!!) 
of the internet structure.  That is staggering.

And they went bankrupt.  This should ultimately 
have an effect on the price of internet service 
(which has always been a losing proposition since 
everybody wants the internet for free---as if it 
were a God-given right or something).

On the plus side, they said that they will 
continue all service at least through their 
bankruptcy protection period.  So there should be 
no immediate effects to the network.

Of course, they laid off 17,000 people, so 
customer service in the event of a problem will 
most likely be sparse at best.

JP