An attachment can be any kind of file, from a Microsoft Word document to a Quicktime movie. Attachments are attached to notes, notes in turn are added to map objects in a buzPAK. Attachments are saved in the buzPAK, so large attachments will create correspondingly large buzPAKs.
Typically you would use an attachment to provide additional information about the map object the note has been added to. For example, if the map object is an item that opens a web page describing an area of research, you can add a note to that item saying "For more indepth information on this area of research read the attached file "Research.doc". You would then attach the Word document to the note.
Item with Note and Attachment
Further Information
See Using Attachments Overview for more information on using attachments in a buzPAK.