The Web Ahead podcast had an episode that covered the current state of
web annotation. Something there might work.
http://5by5.tv/webahead/60

Crossing the thread over to linked author data, this item made me laugh.
http://w3cmemes.tumblr.com/post/76273506486/dave-started-reviewing-open-annotations-today

On Fri, Jun 20, 2014 at 2:28 PM, Eric Lease Morgan <[log in to unmask]> wrote:
> Do you know of a Web-based tool or piece of desktop software that would let a professor post a text in a frame, then highlight words or phrases and link them to a glossary? A quick-and-dirty web page (possibly attached) and link below illustrates the idea:
>
>   http://dh.crc.nd.edu/tmp/glossary.html
>
> —
> Eric Morgan