Jeffrey Lomas, Manager of Technical Services Group at OASIS, was able to confirmed the reasons behind the quiet spell and thanked those who helped resolve the problem:

On November 30th, unauthorized access was gained to the list, and the entire subscriber database was maliciously deleted. OASIS promptly investigated the incident, closed the security hole and restored the list.

I would like to thank those of the XML-DEV community, OASIS staff, legal council, and law enforcement who contributed to the fast resolution of this situation and helped restore XML-DEV services.

Lomas also stressed that supporting the XML-DEV list was high priority.

The list has now been restored, so normal service should have resumed.

Update: Several people have reported that they are still not receiving messages from XML-DEV, indicating that the list has not been correctly restored. To check your current subscription status use the XML.org subscription manager.