Threaded Comments ---
As mentioned on the chatroom last week, I think a big trend coming to WP is learning to Style your comments section, and adopting Threaded comments, and adapting old themes to use Threaded comments. People are going to want new styles to handle Threaded comments and make it look attractive, useful, and make sense what the sequence is. So you want the "date" to show up, but you don't want it to be overwhelming where everything looks out of order because the dates can appear jumbled with Threaded. You may want the Replies to be more Indented, but you don't want crazy indenting back-and-forth all over your page, it starts to look like a zig-zag.
There are many new examples coming out.
Intense Debate is one of the leading examples, that has the ability to set trends because of wide userbase.
I don't know yet if (or how) Intense Debate comments can be styled on your own WP. I tried I.D. briefly and I liked their Comments style alright but it wasn't perfect for my blog. I would need to customize the look of it before using it.
WP 2.7 threaded comments will have some kind of default structure (if not "style"). What are comments like in WP 2.7? Not only the question of how to make your theme support Threaded comments, but how will the Threaded comments be styled, out-of-the-box? How do you re-style them?
I noticed Lifehacker.com has some cool Threaded Comments action. Check them out Jeffro. Under a comment they have another line with a drop-down Plus symbol. " + Replies from Dgold and Jeffro". You click the + to see the replies. Kind of cool.
Just one example page that has it, (See also any individual post that has comments)
NOTE: I am not saying Lifehacker is WordPress, I don't think they are..... just saying it's an example of trends in Threaded comment design