Facebook has become extremely popular, with over 350 million active users worldwide. If Facebook were a country, it would be the third largest in the world, behind China and India. More than half of UK Facebook members log on daily. Facebook's success is largely due to its ability to connect friends and allow information and photo sharing between large networks of people. The more users that join, the more valuable Facebook becomes due to the "network effect" - the more people that join, the more connections each user can make with others.