Regarding comments, if you use Google Chrome and you're a keyboard-centric user, you may try my simple extension (it waits for some improvements [like switching from localStorage to indexedDB to support unlimited storage -- see http://crbug.com/58985, easy access to highlighted comments, etc.], sorry, lack of time), which helps me "remember" the state of comments, so e.g. I can easily skip to unread ones at the current page.