Per Sarah's Knitting Blog at About.com:
"A story on yarn bombers in the Vancouver Sun raised the ire of some more traditional knitters who said the knit graffiti isn't attractive, may actually harm the trees and is a waste of good yarn that could be better used knitting for a person in need rather than a lightpost"
I say- what a bunch of hooey! We need to be extra strong on World Wide Knit In Public Day to turn them into knit graffiti lovers!
