Just last year Amazon in the UK was offering special referral bonuses to employees referring black people specifically for example. I saved the emails for posterity.
For managers of technical roles, they're also a strong push to promote women as fast as possible. My manager has told me about every woman in my team that he wanted to fast track their promotion. I've never heard the same about any of man, regardless of their skill. Of course I recognize that's more anecdotical than the referral thing, but it definitely exists.
