There is absolutely no shame in self-promoting your work, as long as it's not spam or plagiarism or anything of that sort. I look at my Steem account as more like a business, and the content I create is my product. Business always advertise their products and there is nothing wrong with that. If the product is bad and people don't like it then they will lose money and eventually stop. On the other hand if it's a good product that people like their ads will generate a positive return and they will grow and be able to buy more ads!

Maybe I should make a post about this concept too...