Reportedly, via a WebmasterWorld posts, there has been a significant drop in ad impressions noticed from sources in the Mid Atlantic to the Northeast areas of the US. There are literally a couple threads on this at WebmasterWorld, including here and here.
What caused the outage? A huge fire in one of the large data centers that house and power that region of Microsoft adCenter (Windows Live Search ads).
After much prodding and some fairly heated exchanges, the support rep, whom I will not name, told me there was a big fire in one of the major data centers in the east coast that feeds adcenter ads, all servers were burned and data destroyed. This does not mean your ads and data were lost. It means the distribution part of the service is disrupted.
WebmasterWorld's official adCenter representative, adCenter411, claimed the fire was not true. adCenter411 said, "adCenter did not experience a fire in any of their data centers." But she did add what she feels is the issue.
There was/is a delivery issue, now partly resolved, that adCenterEU and I are still looking into for some of you in the UK. I'm sorry for the confusion and misunderstanding, but please be assured that no servers or data was lost.
They say no data has been lost, historically. But lots of potential business has been lost since the fire. I am sure neither side is happy, Microsoft and the advertiser. I just hope they get things going again soon.
Forum discussion at WebmasterWorld.