Using telemetry built into Windows 10, Microsoft sought to improve the features and overall experience of the operating system through automated uploads of data. This capability is provided using the Diagnostic Tracking Service and is complete opt-in.
Last month, Microsoft delivered some optional updates to Windows 7 and Windows 8 users (KB3075249, KB3080149 and KB3068708) that would provide the same telemetry data. Even though the updates were optional and the telemetry service is opt-in, and there's been a lot of hubbub around Windows 10 privacy settings, some users have taken offense to the inclusion of telemetry services in Windows 7 and Windows 8.
For those that don't want to participate in providing automatic feedback to improve the operating system, Telemetry can be turned off completely.
To do this:
Run the Services desktop app.
Locate Diagnostics Tracking Service in the services list and open its Property Sheet.
Stop the Diagnostics Tracking Service and then change the Startup Type to Disabled.
Additionally, Microsoft provides a GPO for Windows 10 to turn this off. The GPO is located at:
Computer Configuration>Administrative Templates>Windows Components>Data Collection and Preview Builds> Allow Telemetry
A GPO is not supplied for Windows 7 or Windows 8, yet. But, savvy administrators can create their own GPO for the following registry key:
Open the subkey corresponding to the service you wish to change, and modify the value of 'Start' to equal either "2" (for automatic), "3" (for manual) or "4" (for disabled).
Additionally, you can use PowerShell to stop the Diagnostics Tracking Service and change the Startup Type to disabled:
set-service diagtrack -startuptype disabled