The Rapid Search is worth meeting: one click search for the most popular search parameters on PW.
There's also an article laying out why PW is a much better buy than Google, and articles on bidding strategy.
For the tech inclined, there is a piece of software to assist with ad placement efficiency.
One thing I'm noticing is that there is a disparity between the traffic PW reports for my sites, and that reported by Google Analytics. One site was a dud when I placed ads on it with PW, but Google Analytics reports it as a top referrer to one of my sites. I sought but did not find a discussion of this on PWT, so I have asked PW for an explanation, if there is one. I'd be interested to hear from others who have noticed this phenomenon.
Google is also showing me with substantially more page views than PW. I'll report back when I understand more.