Their role involves searching for weaknesses or security gaps that could be exploited, and they aim to rectify and close these potential vulnerabilities before a product or system launch. In particular, Microsoft uses the term to refer to the Computer Security professionals they invited to find the vulnerability of their products such as Windows.
The Blue Hat Microsoft Hacker Conference is an invitation-only conference created by Window Snyder that is intended to open communication between Microsoft engineers and hackers. The event has led to both mutual understanding and the occasional confrontation. Microsoft's developers were visibly uncomfortable when Metasploit was demonstrated.