tools

I just saw this: http://drupal.org/project/annotationfield

From the description:

Want to highlight text, clip a video, or select a section of an image? This module is CCK nodereference on steroids. Annotation Field references not just a node, but a specific revision, field, and intra-field information (like a portion of text).

If you've never herd of Diigo.com (as I haddn't before last week) then you should probably go and research it a bit. It's like delicious on steroids and integrated better then any product I've found yet. This has been posted on here because I've created a drupal in education group: http://groups.diigo.com/groups/drupal-in-education