Ads vs spam... there's a difference
I remember when Microsoft rebranded Hotmail to Outlook, and all I saw henceforth were ads featuring other Microsoft products and services.
I surmised that Microsoft was filthy rich enough to not need additional ad revenue from external sources, and there's no better promotion than self-promotion to a captive audience.
We saw that come into fruition with the 'Get Windows 10 now!!!' spam. Once upon a time people would install Lavasoft AdAware or Malwarebytes to deal with that kind of 'promotion'.