Is it possible that the reason that Google paid way over the odds for double click is down to the fact their Ad Words may be losing traction?
I have said for a while that advertisers are going to see that noone clicks on them - i clicked on one once to see what would happen. Funnily enough, in a discussion in a bar last week almost everyone i was with had done the same.
DoubeClick offer a far more invasive advertising process (check your cookies) and maybe this is what Google sees as the next requirement for the next step in their advertising campaign.
In other words, I think the purchase was a logical one for Google, but whether a re-evaluation of how advertising itself is done on the web would have been a better move is something i would question. And Google would have been a company that could have done that!