I'd love to hear input about this issue as well.
The general wisdom is that if one is trying to sell the domain, simply have a parked page that only provides selling info, not ads.
My recent experience, though, makes me wonder. I tried the Dan Hybrid pages over several weeks. There was a significant increase in traffic to the domains as a whole, after adding the integrations. When I reverted back to the Dan landers, traffic again dropped dramatically.
So, does having the hybrid lander help sales?