Shares in Facebook, the world's biggest social media website, will begin trading Friday at $38 apiece on the Nasdaq Stock Exchange.

Facebook's initial public offering — the opening price at which average investors can buy a share — will raise about $16 billion, making it the most lucrative IPO in history.

Some analysts expect millions of Facebook shares will be bought Friday because of the high demand to own part of such a ubiquitous and recognized product. The stock will be traded under the symbol “FB.”

But others are advising clients to wait and see whether the company can still continue to grow and how much advertising it can sell before buying shares.

Facebook's chief executive, Mark Zuckerberg, started the website in his Harvard University dormitory room just eight years ago. It has since grown to more than 900 million users worldwide.

They use Facebook to post photographs and write details about their lives, often reconnecting with long-lost friends and family members.