I was working on a blog addon service that required adding a small javascript snippet to the page to add a button on the side (like GetSatisfaction or UserVoice

I was working on a blog addon service that required adding a small javascript snippet to the page to add a button on the side (like GetSatisfaction or UserVoice) and found that this was possible on almost any service except WordPress.com. I'm well aware that letting users add js to their sites is a major security issue, but it seems like something that would also have a lot of upsides.