europeforvisitors - 2:05 pm on May 6, 2005 (gmt 0)

Thought about this: What if one of the content URLs is sending you people who visit then come back later to buy...are we deleting a potential profit center if they send a large amount of traffic our way, but it converts later :)

You raise an interesting point. A recent DoubleClick study on "search before the purchase" showed, among other things, that a majority of purchasers complete their online research at least two weeks before the "purchase event" and only 23.1% buy during the same session.

Still, if such behavior is general (as the DoubleClick study suggests that it is), we can assume that what matters for tracking purposes is the [i]difference[[i] between conversions for traffic from various sites, not the raw conversion rates. In other words, if Site A has a better conversion rate than Site B, it doesn't really matter that more than half of Site B's referrals come back later to buy, because that's likely to be true of Site A's referrals, too.

Also, a "conversion" for AdWords/AdSense purposes doesn't have to be a transaction. It can be any trackable "business action" that the advertiser defines. If you're a travel agent selling luxury cruises, the odds are remote that a prospect will come to your site and buy a $5,000 or $10,000 cruise on the spot. What really matters to you is the fact that Site A is producing leads (inquiries, for example) while Site B is referring users who look at the home page and bail out.

Side note: As an AdSense publisher who spent 20+ years in the ad business, I've been among those who have been lobbying for advertiser controls since 2003. It's nice to see that Google is finally starting to give advertisers the kind of domain blocking that publishers have enjoyed since the beginning. This may be a small step toward making the content network more appealing to skeptical advertisers, but it's an important one.