I just used this preview tool for the first time and it looks to me that this tool is not a great thing for an adword advertiser. People who use this tool may click out of their curosity ads generated by the preview tool on that page and thus advertisers have to pay for a invalid click. Does anybody knows if google actually charges advertisers for clicks from this tool or not? I think they should not charge anything from advertisers from clicks generated from this tool.
I LOVE this tool! To think... Google actually lets you view what ads will be shown before the page goes live. What a gift! Yahoo needs a feature like this.