BlogWatcher feature survey

I haven't made many changes to BlogWatcher recently. Well, not changes that would be visible to a user, anway. So I was thinking about directions that I could go, and I wanted to get some feedback.

Here are some of the things I'm thinking about

• A "preview" pane. That is, instead of the way the interface is today, with the contents of the articles (or as much as is available) all shown on one page, I could reduce it to a simple author/title type display. Clicking on the article would pull the actual page into a preview area on the screen. Those of you who use "Outlook" for email should be familiar with the concept I'm talking about. Of course, I know some people wouldn't like that, so I'd probably need some sort of method for switching between the two "looks"
• Related to the above, Marking posts read/unread. Along with that, there would probably be a new "subscription" showing just unread posts.
• More feedback. BlogWatcher is doing a lot "behind the scenes" as you read and delete your posts. I've put some rather sparse status messages in to give some idea of what it's doing, but perhaps more would be useful. In particular, I'm thinking about what happens when you delete/undelete a post. It looks immediate to you, but it actually takes some time to exchange the messages with the server, especially if it's busy. Closing your browser or leaving the page while one of those messages is "pending" could cause the action to be effectively cancelled.
• Saving old posts. Currently, posts are available as long as they're still in the feed provided by the original server. Typically most feeds have the most recent 10-20 posts. Older posts are removed from the feed, and so removed from BlogWatcher. Does that older, historical data sound useful to anybody?
• Post categories. Many posts are categorized by the authors. Would exposing that information be valuable? I could put it into the body of the post (fairly easy) or make new "subscriptions" based on the categories (harder, but do-able).
• User-assigned categories. Would it be useful for you to be able to tag a post by your own categories, instead of (in addition to?) the ones assigned by the post's author?

Your thoughts and suggestions are welcome. Some of these things are fairly involved to develop, so I don't want to spend a ton of effort if there's no interest.