30041 is a zettel - an index card of information, similar to an Obsidian note. 30040 groups zettels together, which means that individual notes no longer are in isolation, you can chain them together, like sections or paragraphs of a book can be chained together. Or you can create a collage of notes you think are related. the idea being - not only can notes & ideas be linked together with hyperlinks or tags, they can be contextualized in the form of an article "this note belongs to a larger narrative". Also, you can decontextualize articles "this paragraph is super important to me more than the rest of the article, i'll group it together with related ideas, while simultaneously pointing to the original source/context it comes from" So, as you peruse someone's article/collage of notes, find something with high signal to you, you can go directly to the source where it was written and absorb learn the context it comes from. A highlight can sit on top - it functions as a "hey look here at this high quality idea from this source" to your followers. Highlights can be a subset of a note, or across multiple sections of an article. Highlighting overlays over articles are definitely something we'd like to have as well.