DISQUS

Not only do I think this is useful, I wanted to create a Facebook
application to do exactly that. I was going to call it, "Why aren't we
friends?" Unfortunately, you can't get your friends' friends list
through the Facebook Platform, so I was unable to create the app.

How does one get to this feature? I don't recognize where on the site
the screenshot originates. Are you sure it's real?

Facebook apps peaked months ago. I'd say that less than five percent
of the apps that come out now are with anyone's time.

In addition to separate privacy settings for each friend list, there
also needs to be more integration of friend lists into other parts of
Facebook. For example, I should be able to invite all my friends from
one list to an event, or a group. As well as the ability to select a
specific list in the fb:multi-friend-selector when sending invitations
to use an application.

I don't think I would really count that as AJAX.
To be considered as proper AJAX, it has to use the XMLHttpRequest (or
the IE equivalent). However, what Facebook has done is put all the
data for the entire photo album on the page when you load it. Open up
an image, and look at the pages, source. Near the bottom of the page,
you'll see inside a tag, something like this:

onloadRegister(function() {new Photostream($("myphoto"),
"http:\/\/photos-d.ak.facebook.com\/photos-ak-sf2p ...

This is probably what I would have done as well. I think it's great.