Why are you looking here? I don't know what you are doing here. Only God/Wotan/Allah/etc. knows where god-knows-where is. Jeez. Didn't you read that the first time around? It's Captain Obvious stuff if there ever was such a thing.
Now if you're looking for something you lost, I really can't help. Some smartass will tell you it will be in the last place you look. Hahahahahahahahahaha! Don't look at me like that. Just start looking.
If you're just throwing out the phrase as a generalist description of someplace, that's something else. But you're just going to make Grey Aliens curious about what you mean and before you know it, you'll be abducted and off to god-knows-where. Ironic, eh? Serves you right.