I have been thinking about web annotation. I envision a social service that allows you to annotate any webpage, share your annotations with a group of friends, and use this both as a form of artistic expression (web graffiti) and as another level of online knowledge transfer. These annotations could be text based or graphical. Ideally, I’d like both, where you could simply draw on the page, or type in text, and have it stick with a little mouse-over date/time stamp. I know the technical challenge of overlaying data on dynamic content is imposing, however.
Now, a site called Mystickies [via Goggle Blogoscoped] is trying this with floating text boxes — sticky notes. Their service isn’t collaborative or sharable yet, which is a shame, but it’s a start.
There are some other attempts at online annotation, such as the Annotation Engine. However, the Annotation Engine doesn’t have social controls or groups, so the quantity of annotation — spam, graffiti, whatever — grows out of control. It’s also old and kind of broken. I think a good system would use a karma and interest threshold approach, similar to slashdot, to decide what to show you.
Another fun project is wikalong, which I am a big fan of. It’s not on-page annotation, it is a sidebar wiki for every page on the internet. They simplified the annotation problem into something manageable, and then pulled it off.