Twitter's controversial new timeline, which doesn't display tweets exclusively by their time, is now headed out to users. With this timeline, posts are ranked by their quality and time, meaning a lot of them will be displayed out of order. Twitter has upgraded its "while you were away" algorithms for use with this feed.
Your overall timeline will not be filled with entirely out of order tweets. Instead, the first section of your timeline will highlight more popular posts. Twitter is leaving the timeline off by default for now, but you can enable it by clicking "show me the best tweets first."