martinibuster - 5:03 am on Jun 4, 2012 (gmt 0)
So in May I removed those ads, and used image ads only.
That's to be expected. There's less competition for the ads.
I would urge you to not give up. Add the text links back in to increase the competition and try to improve the earnings with different layouts. Create channels for testing various versions. For instance you can try to separate the ads from whatever's around them with five or more pixels. Another text would be to add a border around them with the words advertisement to see if it improves. Then another with the same border but the word Sponsored.
But also, please research the keywords used to access your site to see if there are any changes, research any buying trends, news trends, anything that may have changed.