Microsoft"s Bing engine is quite popular, while the joke is that nobody uses the service in favor of Google, according to Alexa, the site is the 23rd largest in the world. So when the site"s operations are impacted, it affects a large number of users no matter how long the engine is down.
Earlier today, Bing"s search results were not returning queries for around fifteen minutes. The disruption not only impacted Bing, seeing as Yahoo"s search uses the Bing backend, it"s queries were only showing Tumblr results (Yahoo owns Tumblr). Further, Cortana was unable to perform basic actions as well because of the Bing disruption.
This is not the first time that the service experienced an outage, in January, Bing (and other Microsoft services) was knocked offline for a brief period.
These types of outages, no matter how short, can be expensive for Microsoft as they miss out on searches which generate revenue through advertising. Also, there is likely an SLA (service level agreement) in place with Yahoo where outages can cost Microsoft as well.
Clearly, Microsoft would like to avoid outages such as this for obvious reasons but with two incidents occurring this year, there is plenty of room for improvement.