That's a good question.
I noticed it was down too this morning and then disconnected my CM. Now that the servers are alive again, I went into CM and received a tiny validation... like only 30 items instead of 35,000 and it's completed now as I type this. This makes me wonder that if CM doesn't reach the servers after a too short a time period, TADDaemon will start validating assets immediately upon the next connection.