a) Whitelisted individuals, such as the team implementing the new feature. You can get verbatim feedback from your team members. b) Company employees, as they are typically more forgiving if there are bad bugs. c) Beta users or insiders who tend to be vocal and loyal, who want to see new features sooner, and who are usually willing to give feedback. d) Data centers to isolate interactions that can be challenging to identify, such as memory leaks (death by slow leak) or other inappropriate use of resources
