branko said:
>   I would assume this works the way
>   the creation of any other educational material works:
>   teachers sit down and write the stuff.

but once you've done that,
you want your students to have
a tool that presents the annotations
alongside the text to which they refer.

preferably a tool that then lets _them_
edit them, or add their own annotations.

and finally, a tool that lets everyone _share_
annotations, perhaps even _pool_ all of them
-- within a single class, or across many years --
perhaps in such a manner that the annotations
themselves can become an independent e-book.

-bowerbird