Kayak’s burgeoning effort to turn the metasearch model on its head by facilitating some aspects of consumer bookings will go much further than its mobile app, and eventually could permeate its websites.

That’s the word from Kayak co-founder and CEO Steve Hafner, who says “assisted bookings” will first be trotted out in its pending launch of Private Sale, will be woven into its mobile app “soon,” and will be launched on its websites, too.

One aspect of “assisted sales” that hasn’t been thoroughly vetted is that the move could be a significant boost to Kayak’s behavioral advertising efforts, and could be subject to some push-back from partners.