Microsoft providing Windows 10 Technical Preview release under Insider Program in order to collect feedback from users and help shape the final version of the operating system. According to Privacy Statements for Windows Technical Preview, Microsoft is using build in keylogger to collect users’ data including what you typed, apps for compatibility, and collect voice information when you use speech to text.
Microsoft has issued a response to WinBeta, but did not clarify anything. This is what they said:
The Windows 10 Technical Preview is a pre-release build of the OS designed for testing, evaluation and feedback. We use a variety of security technologies and procedures to help protect your personal information from unauthorized access, use or disclosure. For example, all data sent from the Windows 10 Technical Preview to Microsoft is encrypted in transit and we store the personal information you provide on computer systems that have limited access and are in controlled facilities.
Once you download Tech Preview and become a member of the Windows Insider Program, you provide information about how you use the product, including what devices you use it with, along with your detailed feedback to make adjustments before we launch the product.
Although the feedback being collected in Windows Technical Preview will only occur within Technical Preview period. Once Windows 10 launches to the public as RTM, the data Microsoft collects will be removed from the operating system.