But to others? What's so harmful to put it on top for some time?

Are you referring to so-called "fairness" here? In my opinion, it is on the moderator's discrete to determine if a post is valuable enough be to pushed to top. One may doubt the the value, as it is subjective anyway, but there is no reason to say "难道是因为他照片拍的很美?还是因为作者给了华新赞助,所以可以登广告?"

"I believe there are some article better than that one?"
- For example?

Whenever it comes to subjective measures, there is really no right or wrong. The value of the post can be considered to be the actual photos? Or it can be anything you see inside it. In my opinion, it can be at least considered a good example of self-advertising to some extent. So what's to argue about pushing a demo?

Don't misunderstand my words.

1) Yes and no. Yes, because that's the basis after all. No, because fairness itself is subjective too. Given the limited space, it is impossible to push every book-selling post. So I consider it reasonable to pick only some to push. Those not being push are merely "less valuable" maybe, while no one has ever denied their value in any way.

2) Yes and no too. Yes, because that's the right given to a moderator. As a moderator, the right to respond to posts based on his own idea is the basis of his authority. No, because as a good moderator, he also has to consider the overall consequence of his own actions.

Well... My point here is that there is no clear-cut right or wrong in this case. Some may consider pushing a single book-selling post inappropriate, while others may feel grateful for the highlighting of information. I would say it is better not to define this action as "right" or "wrong" in any way since there can never be a global standard that everybody agrees upon.

But in that case, a more complete account is necessary while accusing the moderator, which was not the case as far as I see. The reasoning of 花露水's post was so vague and peculiar that made me felt like joining the discussion in the first place. I hope everybody can be provide better description and reasoning to justify their points in this forum. This will definitely help us greatly. :^)