Blekko is stupid as an idea, you cannot ban 1 million domains in a shot and call yourself relevant. Are they going to deal with re inclusion of millions of sites if the content changes or just leave them out? But I know they don't claim to index everything.
My traffic from BingHoow increased after some changes I made for Google. The thing is with them I rank for the prized keyword, say "Green Shoes" but in Google I'm overshadowed by bigger sites and get tangent ones.