North American MSN users awoke today to find MSN Search was out of commission. The service was down for at least four hours today. Thus far we have been unable to find out why.

First noted at Threadwatch, searches conducted at MSN Search resulted in an error page reading:

This service is currently unavailable.

Our team is working to restore service as quickly as possible. Please try your request again later.

As reported at Search Engine Watch, there is nothing in the MSN Search Weblog noting the outage. The last entry, from March 28th, details the Search Macro feature at Microsoft’s beta search service WindowsLive.

More details as, (or if), they emerge.