I am a big fan of maps. I work for a real estate company, so that should not be surprising. Pictures can usually put information into better context than mere words.
Frank Jacobs, just published a book: Strange Maps: An Atlas of Cartographic Curiosities.
In an interview with Annika Mengisen on the Freakonomics blog, Mr. Jacobs pointed out an interesting compliance technique to deal with copyright and piracy.
When asked about any strange facts about maps that most people might not know?, he replied:
“I don’t know how obscure this fact is, but the London A-Z contains a fictional street on each of its pages, in order to catch out copycats.”
The authors used a little counter-intelligence to ferret out content thieves.