SparkMarketing - 3:16 pm on Jul 23, 2008 (gmt 0)

I have had success on the content network with several clients and at a slightly lower CPA relatively to my search buys. However, I often see the opposite effect on other networks, where search is more effective than content, so you can't generalize.
MartiniBuster is right--you need to treat search and content differently. It is worthwhile to separate your campaigns for search & content because they behave differently.
Content campaign keyword groupings should be more thematic. Consider not only what users might be searching for but what category of web sites or sections of web sites where they might expect to learn about your product or are "receptive" to your product offer--possibly related categories or topics, for example.
Make use of the placement performance report by URL to uncover sites and specific pages on a site that do and do NOT perform. Consider selectively targeting to the sub-domain for the performers. Use site exclusion to weed out those domains that result in clicks but few conversions.
Take the time to look at the advertisements that are running on the sites you see in your placement report. Consider the different ad dimensions and where they are placed on the page and whether it makes sense to offer banner creative to gain better placement. If you find just a few sites are contributing quite a bit of your conversions, you can even consider whether it makes sense to offer the publisher your affiliate program--if you have one, or advertise with them directly to garner better placement/more control.