Per Lambert's request for input:
I definitely like the following two suggestions that you make on your site:
- Currently, the plugin supports only one callout per page. Change this to support multiple callouts.
- Make it easier to pick styles. Maybe some sort of gallery on the settings page so you can pick a style for your callouts rather than having to enter CSS directly.
I would also add support for multiple styles. Maybe I want one style for a box that says "See also ..." and another style for a box that says "Glossary of key words".