The Annotator Demo
How do I use it? We think you'll get the hang of it pretty quickly. It's running right now on this page — try it out by selecting some text and clicking on the note icon. Enter a note and press “Enter ↩”: you should see your annotation as a highlighted piece of text. Hover over the highlight with your mouse to view, edit and delete the annotation.
What happens to my annotations? The annotations on this page are being sent to AnnotateIt an online web service for storing annotations. However it's simple to set up your own store. Check out the Storage and Annotation Format wiki pages for more details.
If that doesn't make any sense to you, then go see the wiki page on Getting Started for more information.