It came to my attention that some answers have the font in gray. What is the criteria for this? I am guessing that it might be low voting, but am not sure. The question with the same down voting is not in gray. Is there other places that can become gray?
As YOU notes, this happens when the score of an answer drops to -3.
The gray text is intended to de-emphasize the answer somewhat, since most readers have clearly not found it particularly helpful thus far. At this point, if the author deletes it, he'll get the peer-pressure badge.