You may have heard about the fury last week over a rumored change to the way Twitter organizes Tweets. The rumor claimed the stream was going to become algorithmic like Facebook, but it appears now that was overblown. Twitter just announced a new feature that allows users to see the "best Tweets" at the top of the timeline, but it's optional and doesn't alter the overall layout.
This feature will be available to users in the coming weeks. Basically, you'll turn this feature on in settings (apparently it won't be on by default) and the app will display the content you're most likely to care about right at the top. How it determines that is not entirely clear. Below the top Tweets, the feed will pick up in reverse chronological order as it always has. Refreshing the timeline will clear the top Tweets and go back to the fully chronological experience.
You'll see a notification in your timeline when the new feature is available. It sounds like this will be dependent on the official Twitter app for the time being, but perhaps third-party developers will be able to add support as well.