Hi friends , Today I'm with an Important News , How to change the ads that Displays before every posts in thesis theme.
First go to Blogger
Then Design---->Edit Html

In the Most of the Thesis Theme it will display HostGator ads
So now find this Code
<a href='http://secure.hostgator.com/~affiliat/cgi-bin/affiliates/clickthru.cgi?id=smalwayz
Change this Url , To which you want that ad to go
Then Find for this code
http://tracking.hostgator.com/img/Discount_Shared/Hostgator-new-_AN--300x250-.gif
This is the Image Preview of the ad , change this to your Image url
Now very Important thing , You should change the adsense  Id
Now search for this code
google_ad_client = &quot;pub
after this code you can find some numbers Example saying 5551438321907005&quot;; 
Change that number to your id and Below that also you can see those numbers change that to your's That's it Your ad  is Changed Safely!