Vile Villianous Vials

Here's a weird thing...around North and Northwest Portland, vials have been seen fastened to street signs. No one is sure why they are there and what purpose they could have. Theories range from marking locations to buy crack (it's kind of hard to put up a billboard) to preparations for a terrorist attack on our fine city, to offbeat art.

Whatever it is, its got people talking. What's your theory?