http://lh3.ggpht.com/_E0dlF4_71TI/SoOJGrRBxeI/AAAAAAAAKQs/Eg9ZfuveNbE/s400/Fullscreen%20capture%201382009%20112522.bmp.jpg

Google is being desperate.

It had been spotted already:
http://googlesystem.blogspot.com/2009/06/blogger-starts-to-show-ads.html

Besides, why see ad after published a post causes problem? Your blog's visitor won't see it, and it doesn't clutter the interface.