I'm not sure what you mean by that. Most reading material is just fine as a regular post and can't be a Show HN, thats very near the top of the thing I linked:
On topic: things people can run on their computers or hold in their hands. For hardware, you can post a video or detailed article. For books, a sample chapter is ok.
Off topic: blog posts, sign-up pages, newsletters, lists, and other reading material. Those can't be tried out, so can't be Show HNs. Make a regular submission instead.
Things that can't be Show HN can be perfectly fine regular HN posts, just like this thing already is.
On topic: things people can run on their computers or hold in their hands. For hardware, you can post a video or detailed article. For books, a sample chapter is ok.
Off topic: blog posts, sign-up pages, newsletters, lists, and other reading material. Those can't be tried out, so can't be Show HNs. Make a regular submission instead.
Things that can't be Show HN can be perfectly fine regular HN posts, just like this thing already is.