This morning I woke up and the first thought on my mind was "If I write a feed reader that allows people to follow a conversation in a blog entry's comments, how will they participate in the conversation?"
I already had some idea that the technology might exist: a long time ago I ran across the Comment API. However, I had no idea if that (or some other API) had ever made it into, say, Wordpress. After following breadcrumbs across multiple searches on multiple search engines, I finally hit upon a blog entry describing exactly what I was after. (TL;DR: he uses Python to post comments to a Wordpress blog using an API.)
It's a very exciting idea to be able to post comments to websites from within a feed reader, and that's something I want to be able to do.