What feature is used to help track which notes you have already seen?

The feature that is used to help track which notes you have already seen is called the "Read Log." This feature specifically helps users keep track of their interactions with the notes, providing a record of what has been viewed and when, which is useful for managing ongoing projects or studies.

The "Read Log" allows users to refer back to previously viewed content, making it easier to determine what information has been reviewed and what is still pending. This is particularly beneficial for efficient information management, ensuring that users can easily focus on new or unaddressed notes instead of revisiting the same materials repeatedly.

The other options, while they might suggest some form of tracking or organization, do not specifically serve the same purpose as a Read Log. For instance, "Time Mark" might refer to timestamps but does not specifically indicate if something has been seen. "Note Indicator" could imply a general status or categorization of notes but lacks the direct intent of logging read history. "View History" may suggest a tracking feature, but it does not typically provide a detailed log of what notes have been read, thereby lacking the specificity of a Read Log.