You could share a notebook with your secretary; she will only have access to that notebook, but not your personal notes. However, if you use tags extensively and organize with nested tags - which I do - then sharing a notebook with your executive assistant is basically pointless. Don't get me wrong - I LOVE Evernote! ALOT! But tags are a complete mess across shared notebooks. Tags work great if you are an island to your self. But if you need to work together as a team managing tasks/workflow etc... basically all the reasons you would want to share a notebook, then tags are broken.