You’re supposed to use the comment section for your own comments… all pdf manuals use the “bookmark” function.
Bookmarks are generated automatically during PDF creation from the table-of-contents entries of documents created by most desktop publishing programs. These bookmarks are often tagged and can be used to make edits in the PDF.
I hear what you’re saying, but regardless of common practice, it is -not- semantically correct.
I’m not being pedantic. A ‘bookmark’ is just what it says it is. As I use eBooks more and more I need to be able to find -my- bookmarks (there’s no other way to say it). Publishers have hijacked this function rather than set up proper chapters/sections/etc.