If you've updated Windows 10 to the latest "Fast Ring" build you may notice something unwanted: Ads piped directly into the Start menu. But fear not, I've got a way to kill them.
For now, the ads only appear for those people in the Windows 10 Fast Ring who have installed build 10565 of Windows 10. They show up in the space just below the Most Used section on the left side of the Start menu, and they're ads for Windows apps from the Windows Store. Eventually everyone with Windows 10 will see them, when build 10565 is released to the general public.
The ads will be around for the long haul, but apparently won't infect the rest of the operating system. Microsoft told the Inquirer "We will continue to offer Windows Ads in Apps on Windows 10. Beyond that, we do not currently have plans for advertising in Windows 10." Microsoft claims that it's not being paid to show the ads. So why show them? Microsoft say they are "programmed by Microsoft to help customers learn and discover new features and apps to enhance their Windows 10 experience."
If, like me, you don't consider ads an enhancement to your "Windows 10 experience" you'll want to turn them off. It's easy to do. Right click the ad (which Microsoft labels as "Suggested" rather than as an ad), and then select "Don't show this suggestion," if you don't want to see that particular ad anymore, or "Turn off all suggestions" if you want the ads killed altogether.
You can also go to Settings-->Personalization-->Start and then turn off "Occasionally show suggestions in Start."