The site is Hacker News - not Programmer News. I understand that there is obviously a strong lean towards programming when thinking of hacking, but hacking can apply to broader topics than just programming. A lot of people are interested in eBooks and marketing and if the post helps you think about those things in a new manner and "hack" the methods of writing, publishing, and marketing your eBook, then I think it's a valid thing to post. If you check out the guidelines for posts on HN, you will see:

"Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity."

I think that a lot of these posts will satisfy a ton of people's intellectual curiosity. If it didn't, why would it make it to the front page in the first place?

Not to mention that if you extrapolate some of the ideas found in these sorts of posts, you could potentially apply them to things like programming and startups. Seems like a beneficial thing to me to have on the site.

I won't go into whether or not some of these posts are that well written or that incisive, but I think a lot of people would agree that they belong here.