Creating the perfect Ajax UI

I am looking at this meme page about river of news.

Here are the things I like about this UI:

1. The name of the page is SEO-friendly, which is why I could find it in Google
2. It hides extra stuff until you need it – for example the voting icons only slide in if you hover over the post itself
3. The voting explanation text is hidden – unless you hover over the voting area, that's the only time you need to see the details
4. The overall usefulness of the post is indicated by an icon

Things I don't like about it:

1. Posts that have been voted not useful are not hidden from sight but still available (condensed like this)
2. Hovering your mouse doesn't pop-up (using Ajax) the entire post to read it quickly, you have to go to a new page to read it
3. You can vote without actually reading the whole post!
4. Hitting "next page" loads a new page (not 2.0 Ajax-ified)

What are you likes and dislikes in an Ajax User Interface?