Google has quietly posted a notice that they are “sunsetting AdSense” for Google Sites. It appears that after August 30, 2013, the AdSense ads on Google Sites will no longer be able to be edited or added to. You can delete them.
It is however unclear if you leave the ads on the site, will they still earn money for you after August 30th.
Here is the notice:
I’ll try to get more information from Google on this change. Although, I think the reason is that I assume the majority of the sites on Google Sites are spammy.
Forum discussion at WebmasterWorld.
Update: Google has updated the message to clarify that ads already on Google Sites will continue to earn money. Here is the revised text:
