Search pro John Ellis was loath to use AdSense after seeing some of the poor conversion numbers, but has since seen his content network ads "performing
just as well, if not better than" his search ads.
Ellis lists four tips for getting the most out of content network campaigns, including steering clear of the big, branded (and often more expensive) sites in favor of longer tail; running performance reports to figure out which sites are underperforming; and most importantly -- keeping the contextual and pure search budgets separate.