I like the immediate connection to context, but it has some sore-thumb-sticking-out flaws.
-As already mentioned, the expanded comment itself obscures the very context a system like this is designed to provide.
-It also obscures the comment unless you click on it, and provides very little reference for finding a comment you've already looked at, and that you want to see again. Telling your users too little about what they're clicking on and what they've already clicked on is breaking one of the most basic commandments of good web U.I. design.
-As already mentioned, the expanded comment itself obscures the very context a system like this is designed to provide.
-It also obscures the comment unless you click on it, and provides very little reference for finding a comment you've already looked at, and that you want to see again. Telling your users too little about what they're clicking on and what they've already clicked on is breaking one of the most basic commandments of good web U.I. design.