...or "bookmark and user note function"
You might also rephrase along the lines of "functionality for adding bookmarks and comments" (functionality being a very popular term among US software vendors :-) )

It's not the *taking* of notes that's being discussed here, but the ability for the user to **add** notes. Many of my CD-ROM dictionaries offer this capability, and I use it extensively to add terms that I have found while researching something.

Brandstetter's English language interface for its dictionary CD-ROMs uses "Comments", whereas Publicis MCD Verlag uses "User Note" in its English interface.

HTH