Jack Evans, a Microsoft spokesman, says the company’s plans are benign. He differentiates between the Services Agreement, also known as the terms of use, that was changed on Friday and the company’s Privacy Policy, which was last updated in April.

“Over the years, we have consistently informed users that we may use their content to improve the services they receive,” Mr. Evans said in a written statement. “For instance, we analyze content to improve our spam and malware filters in order to keep customers safe. We also do it to develop new product features such as e-mail categorization to organize similar items like shipping receipts in a common folder, or to automatically add calendar invitations.

“However,” he added, “one thing we don’t do is use the content of our customers’ private communications and documents to create targeted advertising. If that ever changes, we’ll be the first to let our customers know.”

Microsoft’s new services agreement affects only its free, Web-based products, not the software programs that individuals and companies buy off the shelf for home or business use. It covers Hotmail, and its related e-mail service, Outlook.com, but not the Outlook e-mail and calendar program that is individually loaded onto computer hard drives and widely used by corporations. Bing, its search engine, is covered, but Internet Explorer, its browser, is not.

Microsoft’s pledge not to use the data from its Web services to target advertising has some credibility, given the company’s broader privacy initiatives. The company has said it will include a “do not track” feature in its new Internet Explorer 10 Web browser that prevents online advertising companies from monitoring the browsing habits of users so they can target promotions. Microsoft has made “do not track” the default setting on the new version of Explorer, a move that has caused a firestorm among online advertising companies.

Microsoft’s push to provide better privacy protections for consumers comes at a time when its efforts in Internet advertising have sputtered. Online advertising remains a small fraction of Microsoft’s overall business, accounting for $2.6 billion, or about 3.5 percent, of the company’s revenue during its last fiscal year, which ended June 30, according to Microsoft’s filings with securities regulators.

But it is easy to see how Microsoft customers might be confused, because the different divisions of Microsoft that draft and oversee its user agreements and privacy policies did not anticipate that the changes in the services agreement would raise privacy questions.