Suspend - Inject - Resume
a.k.a. the lightbox effect (or greybox, or thickbox).
When the need for a secondary task comes up in the main task flow, suspend the main task, dim the main task interface, and present (highlighted and focused) the interface of the secondary task on top of the main task interface. Once the secondary interaction is complete, remove the secondary interface via transition, brighten the main task interface, and resume main task interaction.
An environment-wide label/tagging system. Primary manifestations would be in adding and application of labels to content, viewing content by label (filtered search), and managing labels (both personal and system level).
Label Drop Box/Automatic Tagging
A ubiquitous hot spot for dropping selected content (documents, snippets, discussion logs, bookmarks, images, etc.), that would apply pre-defined labels to the content dropped into the box. For example, creating an English 101 drop box would apply the label "English 101" to any content dropped in the box (basically an easier form of label application and overall organization). Something in the vein of the bookmarklet.
Save As Draft
Suspend the main task flow indefinitely and provide a means for the user to immediately pick up from that point in the workflow. Drafts would be offered to the user (probably sorted by most recent) when returning to the interface from which they were saved.