You misunderstood my comment, I had no objection to you advertising your PDF book. My comment relates to the format of your advert. Every other item on this feed is an informative article. Your item is a pure advert disguised as an informative article.
Advertising goes both ways. You need viewers to make your advert effective. If you don't provide me a reason to watch this feed then I don't see your advert and it's pointless.
I refer you back to my original comment. Why not take the time to write a useful article on ClickOnce (that gives me something) and then use that opportunity to tell me about the benefits of your book (that gives you something). Everyone is then happy.