Online social networks change the way people communicate, work and play and social-networking technologies create considerable benefits for businesses, says a special report by the Economist.

Market research shows that people spend more time on social-networking sites that on email. And it's not just youngsters - people of all ages join such networks and the numbers are increasing rapidly.

The experience of Toyota and Sony suggests that people using social networks are more likely to engage with brands than sceptics think. Moreover, the networks produce a powerful viral marketing effect because friends use them to tell one another about things they have discovered. Marketers have long known that such recommendations are hugely important in purchase decisions. This is the effect of word-of-mouth. All this is detailed in the special report.

The Economist's report also argues that social networks create significant marketing benefits, especially for small businesses. Using social networks can help them grow effectively.