SAN FRANCISCO (REUTERS) - Twitter Inc will seek to raise US$1 billion (S$1.25 billion) in the largest Silicon Valley initial public offering since Facebook Inc's 2012 coming-out party, according to an IPO filing made public on Thursday.

The eight-year-old service, the preferred communications tool for celebrities and politicians alike, gave potential investors their first glance at its financials.

Revenue almost tripled to US$316.9 million in 2012, from US$106.3 million in 2011. It said about 65 per cent of its revenue derives from mobile users. But the company has not made a penny in profits since 2010.

The service had 218.3 million monthly active users, on average, in the three months ended June 30. Three-quarters of its monthly active users are considered mobile users, it said in the filing.

Twitter intends to list common stock under the symbol "TWTR."