Timelines can be used in UI for a dozen different reasons. Infographics and historical projects will often use timelines to express important dates or events. Additionally timelines can refer to the interface element found recently in web and mobile applications. Examples can include Facebook’s newest design, or a Twitter iOS client like Tweetbot.
So I’ve put together some really lovely examples of timelines in action. Many of these are based around a specific graphical theme and you can pick up on some fun design techniques.