Displaying AdSense on un-published Pages

I've added several lines of code to this site to guarantee that AdSense ads aren't displayed when I'm working on it. This insures that I don't accidentally click on ads and don't generate any invalid clicks - if there is no ad to display there's no way for things to go wrong.

Up until today I thought that AdSense may have even had a policy against displaying ads on unpublished pages. This may not be as big a concern as I had previously expected though. In a post today on the Inside Adsense blog they share the following:

Before our system can display targeted ads on your pages, our crawler first needs to access your pages. While you're building your pages within your HTML editor, your page hasn't yet been crawled, so you may sometimes see less-targeted ads or even ads in foreign languages.

While I would still actively aim at stopping ads from appearing in preview and editor situations it's interesting to know that AdSense is aware that it happens. I expect they have a method of identifying these types of situations and don't count those impressions towards the AdWord accounts that pay for the ads - chances are those impressions also don't count towards the publishers stats.