I have a couple of ideas for you, to potentially make it more feasible / faster to implement. Two problems: 1) A lot of these sites that you refer to are smal

I have a couple of ideas for you, to potentially make it more feasible / faster to implement. Two problems: 1) A lot of these sites that you refer to are small and the chance of multiple users of a FF plugin going to that site might be unlikely. 2) Unless you have a lot of experience with FF plugins, it sounds like a lot of work for something you may just want to experiment with. So, 1) Make it a destination site, with a simple bookmarklet for grabbing the text and adding questions, etc. It takes 2 minutes to make a bookmarklet that can grab text and will work with more browsers than FF. 2) This way, you also expose neat questions/ideas that are ripe for discussion, from a series of small sites that might otherwise go undiscovered. I understand it's not quite the same, but for a small project, proof of concept, it's a day or two of coding instead of a huge commitment, and it works well even if you have a tiny number of users.