Every once in a while, particularly since the internet shrunk the world down so small you could fit it in your pocket, there comes a phenomenon which very quickly takes the world by storm and gets people talking. Other people hear these people and want to know more. As night follows day, it goes from a niche, little-known pursuit for enthusiasts to something that you cannot avoid no matter how much you try to ignore it. in 2009, that thing has been Twitter. At the start of the year it was mildly popular, and as it comes to a close it is something that has grown wings. 

The "wings" metaphor is an appropriate one, given that "twitter" was previously a word used to describe a noise made by birds. As things stand today it may never go back to being that, because if someone describes a flock of "twittering birds", the image that will form in many people's mind is of a bunch of sparrows with laptops sending each other short comments and links to YouTube videos. Politicians use it to gauge support, news agencies use it to break stories quickly, and writers churn out articles about it. If you don't know what Twitter is, maybe you never will - or maybe you'll go and check it out right now. 

Writing a message on Twitter is known as "tweeting", and people seem to be entirely comfortable with that idea. If you repeat someone else's message by copying and pasting, this is known as "re-tweeting". The jargon may sound idiotic, but by force of numbers it has become the done thing.