[nickstenning]

"Have you considered creating a bit of javascript that any site can embed on their site that would allow a visitor to annotate?"

Yes, we have. It's there on the front page if you scroll down! http://annotateit.org/#develop

"Also, have you considered making it anonymous to start like github:gist?"

Well, you can certainly try out Annotator using the demo at http://okfnlabs.org/annotator/demo/