I recently changed my blog template for http://www.hackcyber.com/. After that Public Serving Ads started appearing. What can be reason for that??? Thanks if u have some suggestion for this.
Try an online page checker - I did and this is what I saw in the report: Spider robots are not allowed to spider the web page. Spider robots are not allowed to follow urls from the web page. Guess that says it all!
Your ads are fine. May be it was the problem with your robot.txt, and now you have fixed it like you said.