Book Marketing at Goodreads

I recently tested some different ads at Goodreads, and it has been a terrific learning experience. 

Goodreads allows you to control how the ads are displayed, and all of mine are targeted toward Goodreads visitors who are fans of the genres and authors shown in the box on the right. Some of these authors wrote books similar to mine, and some are just authors I like.

I spent $50 to set up my marketing campaign at Goodreads, but the money is stored in a pool until users click on the ads. Each click deducts a small amount from my initial contribution.

Goodreads lets you set up multiple ads for one campaign, and that's the interesting part. I wrote different copy for each one and then was able to see which ads were the most effective. 

Here are the eleven ads that got clicks ("CTR" = "Click Through Rate):

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What's even more interesting, in my opinion, is to see the seven ads that didn't get any clicks:

I have not seen a big jump in sales from running this campaign, but I have learned from it, and that in itself has been valuable. 

Which ad do you like the best?