Interactive Technical Manual within a Wordpress site

Hi Guys,

We are attempting to incorporate our Technical Manual within a WordPress site and would like to offer clients the ability to add personal notes, or bookmark pages, that only they can see. Although a PDF has sufficed for many years we now wish to include visual elements that cannot be embedded within a pdf.

So for example, a client has been browsing our Technical Manual pages, and wants to highlight, or make a personal note, referencing some detail on a particular page. He then may wish to share the page, with the reference, to one of his fellow workers, perhaps in a user group. No one else externally browsing the same page can see his notes or bookmarks.

Ideally the Pages will have the Technical Manual Index and Search in a side column which could also include any bookmarks made by the client.

Whilst I can find several plugins that semi perform this task I can find nothing that quite fits our needs.

Some interesting finds were a Postit Note Plugin and a Private Area Plugin.

Any ideas or thoughts appreciated.