What is the world is a Twitter timeline?
When you log in to Twitter, you see a timeline right there on your homepage. We often call this your "Home Timeline", as it appears on your homepage. This timeline is a long stream of all Tweets from those you have chosen to follow on Twitter. Newest messages are at the top; scroll down to view older Tweets. You can interact with messages from within the timeline by replying or retweeting, or by hovering over or clicking a username to view more information about that user.
Note: If you see Tweets in your timeline from users you don't follow, check to see if they are retweets. It's likely someone you do follow chose to re-broadcast that message to you because they found it interesting. Retweets do show up in your home timeline.
Be sure to check out the Twitter Help Center for more tips...