The Google AdSense preview tool
Firstly, it shows what might appear on a specific webpage, not what does appear if you actually have Google AdSense ads appearing on that page. Unless you don’t mind skewing your statistics by visiting your own website, this isn’t a great way of going about it. What I really want to know is what ads are appearing on my website, without visiting the website. And without being tempted to click on your real ads - definitely don’t do that!
I would like a list of ads and their URLs that have been served up on my website by past visitors, so I can determine if the ads are appropriate. I should be able to click on the link (without gaining income or charging the advertiser) and see what their website is about.
There is something else missing from Google’s ad previewing tool: it is limited to working only for Internet Explorer! This is very strange, as Google actively sponsors and promotes FireFox, and Microsoft is one of (if not the only) enemy of Google!