I read about the whole universe being a black hole, what does this really mean?

Question: I read about the whole universe being a black hole, what does this really mean?
- Keywords:
  black hole,
  space,
  universe
Asked by randevsu to Nick on 11 Mar 2014.
- Nick Wright answered on 11 Mar 2014:
  
  I don’t know! It might mean that because we can’t see inside a black hole, and because we can’t see outside of our Universe, perhaps for anything stuck inside a black hole it looks to them like they’re in their own Universe and there isn’t anything outside.

Question: I read about the whole universe being a black hole, what does this really mean?