fabric street art

According to yarnbombing.com, today is International Yarn Bombing Day 2012, and on my way home from the fabric shop I spotted this:

Is decorating fencing with textiles a new street art trend? I ask because I've recently seen this:

And this:
Yes, that is a recent photo, despite the snow. It's from April but in Helsinki, not Manchester.

I don't follow the street art scene, so I'm not sure if this is up-and-coming or ancient history, but it got my attention.