One of the fools over at Fool.com offers up some commentary on what he calls "Google's Potentially Fatal Flaw".
It's an interesting assessment, but I think the major flaw lies in the logic of Rick's article, not Google. Granted, I agree that click fraud will continue to be an issue, and hopefully a more visible one in the future, but as far as his comments about Google increasing their search inventory to the point where all the big advertisers run out of bmoney--leaving just the nickel bids--is ridiculous. There is a lot more demand for most keywords right now than their is supply. The amount of demand for paid keyword traffic grows every day as potential advertisers are bombarded with media hype about how great search is. You know, I sometimes wish someone wouldn't have spilled the beans. It was a lot easier and more fun before everyone knew how effective search marketing is. As far as advertisers bidding smarter, that could happen, but when they do, there will be someone else there to take their top spot and pay just as much for the click. Besides, I think Rick underestimates how smart search marketers are currently.
My personal opinion is that Google won't lose because they get too much inventory or because of "smarter" advertisers. If Google does lose (which seems unlikely at this time), it will be because one of their competitors came in for the kill--not because of any of the industry-related factors mentioned in that Motley Fool article.