Twitter will seek to raise $1 billion in the largest Silicon Valley IPO since Facebook's 2012 coming-out party, hoping to woo investors with rip-roaring revenue growth despite never having made a profit in the past three years.

On Thursday (October 3), they posted the following message on Twitter just after 5pm EDT (2100gmt): "Our S-1 will be filed publicly with the SEC momentarily."

The eight-year-old micro-blogging service, the preferred communications tool for celebrities and politicians alike, gave potential investors their first glance at its financials on Thursday when it publicly filed its IPO documents.

Revenue almost tripled to $316.9 million in 2012, driven largely by advertising. In the first half, it posted revenue of $253.6 million but had a loss of $69.3 million.

But in a typical laundry list of risk factors appended to all company IPO filings, Twitter warned it was heavily reliant on advertising revenue. It said more than 87 percent of its revenue came from advertising in the first half of 2013.

Although its user base was expanding steadily, Twitter warned that the ad prices it commanded from marketers had been falling for the past five quarters, signalling that the effectiveness of its key money-maker, the "Promoted Products" suite, may be waning.

The average cost per ad engagement slid 46 percent in the June quarter, compared with the previous quarter.

Its IPO has drawn multiple comparisons to Facebook, but Twitter appears to have less of an issue with mobile. About 65 percent of its revenue derives from mobile users, it said.

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," though it did not specify whether it intended to head for the New York Stock Exchange or the Nasdaq.

Presented by Adam Justice

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