Create annotations in your content.
Turns footnotes into sidenotes, magically aligning each note in the sidebar next to its corresponding reference in the text.
Easily make your posts annotatable on Genius.
Diigo Online Bookmarking Widget
Creates an annotation link to take out "unneeded" text.
The Live Video Annotation plugin allows you to add timed footnotes to a YouTube video. Visitors can see these notes later while watching the video.
Why is that comment in the trash? If you co-blog, you've probably asked this. The Annotated Trash plugin helps answer that question.
The Annotation WP plugin provides a user friendly shortcode wrapper for the jQuery UI ToolTip Widget as well as the standard UI themes.