A snippet from the horse's mouth:
'How we use personal data
Microsoft uses the data we collect to provide you with rich, interactive experiences. In particular, we use data to:
Provide our products, which includes updating, securing, and troubleshooting, as well as providing support. It also includes sharing data, when it is required to provide the service or carry out the transactions you request.
Improve and develop our products.
Personalize our products and make recommendations.
Advertise and market to you, which includes sending promotional communications, targeting advertising, and presenting you with relevant offers.
We also use the data to operate our business, which includes analyzing our performance, meeting our legal obligations, developing our workforce, and doing research.
In carrying out these purposes, we combine data we collect from different contexts (for example, from your use of two Microsoft products) or obtain from third parties to give you a more seamless, consistent, and personalized experience, to make informed business decisions, and for other legitimate purposes.
Our processing of personal data for these purposes includes both automated and manual (human) methods of processing. Our automated methods often are related to and supported by our manual methods. For example, to build, train, and improve the accuracy of our automated methods of processing (including artificial intelligence or AI), we manually review some of the predictions and inferences produced by the automated methods against the underlying data from which the predictions and inferences were made. For instance, with your permission and for the purpose of improving our speech recognition technologies, we manually review short snippets of voice data that we have taken steps to de-identify. This manual review may be conducted by Microsoft employees or vendors who are working on Microsoft’s behalf.'