If you did straight KW ROI, many of these terms would fail the test as people won't initially buy from these terms.
How many people track the initial KW used to find a website, and then buy on a visit down the road from another ad? If you used the conversion tools, the later KW would get the credit, when the generic one was used to start the interaction between you and the buyer.
I think sometimes people get too caught up in the exact term that made sales, and forget that sometimes it might be a cooperative effort between many KWs.
I don't make as much per customer as I would like on "super keywords" but as longa as they are profitable, I figure it's a great way to gain new customers.
After six months, the campaign finished that phase and we stopped the ads. Then (and only then) I began to see something in the logs: hits to the ad's clickthrough page using the full page title - and that was a very unusual set of words.
So clearly we had a residual amoount of return traffic who remembered the title, no longer could find the ad, and were coming in and signing up after the ad campaign was over.
The ROI for the "super words" campaign did not reflect those sign-ups, but it probably should have -- a point this article makes quite nicely.
One thing you'll *never* see is Kevin writing an article about how it makes sense for many, many large advertisers to manage SEM inhouse.