A lively discussion in the NANOG mailing list just recently ended with the disconnection of Intercage/Atrivo hosting company. This hosting company has been known to host customers with varying ethical standards.
One of the fallouts of this disconnection is that many malware websites are no longer reachable. This means if your computer has been compromised in the past, it may not be able to find its controller anymore. Sometimes, this means your computer won't work at all anymore.
So, if you noticed that a computer stopped being able to browse the Internet over the past week, you may want to check it for malware. Perhaps your DNS isn't pointing where you thought it was.