In light of these predictions, it’s not surprising that Twitter is contemplating some big changes to how it handles content and discourse. Twitter has always been notable for avoiding the algorithmic approach favored by Facebook and other social media. The hierarchy of information on Twitter is clear: the most recent tweets are always at the top, and when you log in to your timeline, the majority of your attention is focused on a constantly refreshing portrait of the moment. Content that is regularly retweeted by people you follow is more likely to appear in any time snapshot you view, and thus retweets are a way of maintaining visibility even as the hierarchy stays time-based.
Via Kim Flintoff