Every day, millions of videos are uploaded to the Internet, but very few of them go viral. If you think that it's impossible to predict what kind of videos go viral, you might be right. But the phenomenon of viral videos is fast-growing, and more people than ever are posting videos online. The whole phenomenon is being studied closely, because there's a lot of money to be made if you can reach an audience of millions with your video. But the key to a viral video isn't how it's spread — it's the content. The mechanism for the spread of viral videos is clear and it's quite different to traditional mass media. Millions of people watch mass media every day and they all see a broadcast at the same time, whereas online videos are seen by a much smaller number at first, and then they are shared with the viewers' contacts. They can be seen multiple times and at any time the user chooses. A viral video is ultimately viewed by a huge, global audience. A lot of people who started out posting videos as a hobby now host adverts on their sites and so they've turned their hobby into a source of income. Later on in the programme, we'll be talking to three people who have done exactly that. But first, the business news headlines.