If you wanted to know what other sources had to say about it, you would have, and perhaps did, look it up yourself (rather than simply being curious what other people in your friends list had read or heard) but just for fun:
My god I love the "logic" in the first link! "I saw a news brief about a neighbourhood in Amsterdam where there was a lot of drug use, and there was a pair of shoes over a wire, so that proves it!" and "This seems proven to me, there were a pair of shoes over the wire near where a drug murder had occurred."
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http://www.straightdope.com/columns/read/1177/why-do-you-see-pairs-of-shoes-hanging-by-the-laces-from-power-lines
http://www.roadsideamerica.com/set/shoetrees.html
("*They* were looking for it, too, but *they* weren't good enough!")
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There's probably more but I had to avert my eyes!