I thought the same thing. Isn't that what they SHOULD have been doing all along? I know they had the drop-down to switch from "most recent" and "top stories", but I was interested by that also. I wonder if they meant something more "grey".
I have 140 friends. I log in a couple of times a day. I have filtered all their crap. I want chronological order.
If I had 1000 'friends' who posted all day, then I would want a way more filtered and special-sauced feed.