> So is Imperva similar to how Kentik operates? What was it priced liked?

It is a nice model as you don't need additional hardware or virtual appliances on-prem, which cuts down on the CAPEX cost. Like everyone else, they price the scrubbing based on your clean traffic levels. Price I have is circa $73,000 a year for 250mbit clean traffic and circa $94,000 a year for 500mbit clean traffic. Reasonably good value if you get attacked a lot - a very expensive insurance policy if not. Yearly pricing is broadly on par with Radware, Arbor and A10 (Verisign).