I hate to bring up the "don't be evil" mantra. That seems long in the past, however I do wonder what the impact is on hiring and retention.
Many people I know have certain moral beliefs that mean that they would never work for certain companies, examples would be:
- military - pornography - social manipulation (i.e. Facebook) - work practices and worker rights (i.e. Amazon) - proprietary approach (i.e. Apple) - lack of open source contributions