Better source material for that article I guess:
http://www.newscientist.com/article/...ons-orbit.html
Their target is a 7 meter wide asteroid.
That doesn't sound worth it to me, though it isn't really dangerous (the small article doesn't give that little bit out so it brings out all the bad thoughts about mile wide asteroids planet killers)
On the other hand that is about the size of a small house I suppose. I just could be off because I don't generally messure things in meters. At least not in the single digits. I use feet for that.