Last year, Microsoft began placing ads in its Email and Calendar programs coming in Windows 10. System users were rightly complaining about unwanted ads that popped up.
According to the company, the ads were part of a "experiment" with the user. However users who had a subscription to the Office 365 they were not part of the "experiment". Coincidental or not, most of the ads targeted the user to purchase an Office 365 subscription.
After months of complaints, Microsoft finally withdrew from the programs. Apparently the "experiment" has ended so far. The Redmond giant has reinserted ads into Email, Calendar, and the free Outlook smartphone app.
In Outlook for smartphones, ads are not only a nuisance for users, but they also hinder the use of the app because ads are not sized properly by placing them above their email, which is frustrating. To get rid of ads, simply subscribe to the Office 365 suite, which leaves the Outlook smartphone app in its "full" version.
This is not a Microsoft practice only. Many developers make their mobile apps or games available for free, but with ads and advertisements. And to remove them just buy the "full" version of the app.
Microsoft has commented that the user can send their opinion through Comment Hub Windows 10, which suggests it may be another "experiment" of the company.