Facebook shares due for stock market floatation
Shares in the social networking site Facebook are going on sale, in one of the biggest floatations ever seen on world stock markets.
Shares will be sold at $38 (£24) each, meaning that Facebook is valued at $104bn (£66bn).
The website has transformed the way in which hundreds of millions of people communicate, but questions remain about its ability to generate profit.
Rory Cellan-Jones reports.