I'll take a stab at it. Do not embed javascript at all! Javascript slows down the webpage, send creepy-tracking-stuff back to the ad network, and gets easly blacklisted in adblockers. We should not trust arbitrary 3rd party javascript code anyways. How about embeddable static images instead? Generate a unique img tag for each content creater, that we can refresh at our end, everytime the webpage loads. Will show a new ad everytime a user goes to the page.