I would like to write a Chrome extension that embeds icons into pages and displays a pop-up when moused-over, similar to the functionaly provided by the Tweetbeat Firsthand extension. I've had a look at the developer docs but I can't seem to find a description of how to embed icons in a page. Could you point me to a description of the API to do this or, better, a tutorial?
This sounds like the perfect job for a Chrome content script. Just use something like JQuery to manipulate the DOM to add an