7th and Cross Streets, Little Rock, Arkansas.
When the building to the right was torn down, a “ghost sign” appeared:
Here’s another one on the Maypearl Feed Store in Maypearl, TX:
And one in Trinidad, CO:
“Ghost signs” are a very popular subject with photographers; some places like San Francisco even have databases of such signs.
The Old Wolf has spoken.
Playing in the World Game 
Littlerock actually is a Ghost Sign, because you have the Before and After photos, and you can see the remains of where the roof flashings overlapped with the jaggy black line of tar…
The other two aren’t in my book. Now they almost certainly are real old painted ad signs, the original Billboard that Dr. Pepper paid the store owner to have painted on a blank side of their buildings, and may therefore fit your definition of a Ghost Sign – But they haven’t been hidden away for decades by other structures, and then re-revealed.
At Trinidad, CO Dr. Pepper even paid to have 3 lights mounted to illuminate it at night – but that’s also the proof that there wasn’t an adjoining building hard against the sign. The lights and power meters and service line on the side of the building would all have to be relocated to put up a zero-clearance building there.
And Maypearl TX example faces a side street, and the building has windows. That leads me to believe the side street has been there the whole time…
Pedant. For me, a ghost sign is any one that has been there for so long that it’s fading. It’s possible that the Maypearl one just looks old, but it fits with the rest fo the article.
To-meh-toe, Toh-Mahh-towe. Ghosts disappear and then reappear later, and that’s what I based my opinion on. Words have meanings…