What do you think about adding a new column in the manga lists in which we can write notes? Here you have an example taken from MyDramaList. I think it would be very useful to note your favourite chapters, your first impressions or a few other details you can't write anywhere else.

Or even be able to enter the notes on the manga page directly. (so that only you are able to see it)

I think this would be really good. I would enjoy adding notes for my future self.

This would be great! I often forget key things between chapters or just want to note my favorite moments or thoughts so a notes feature would be very helpful.

I think there is a way to view your lists with all your comments to the side. But I don't remember exactly how 😕 .
You can also write it with spoiler tag and put your opinions on the forum as a post t (just before the comments) with the chapter number of the chapter or the ark.

This great. I would like to note down sth that only I can see too. Directly in the series page is great idea 😊

i would love this. it’s very helpful on MyAnimeList and MangaGo for stuff like why I stopped reading a series, or key scenes i want to go back to, or where I need to go to read/buy it.

Bumping this up because I think it would be very useful for users to keep track of their series. Sometimes I don't want to write out a coherent in-depth paragraph review and instead use key words to help me recall what I liked about the series, however, it would look like gibberish to the public (and maybe even distracting).

Perhaps instead of adding a new section/column, maybe give us an option to submit our comments privately or publicly?