LinkedIn has filed a registration statement with the Securities and Exchange Commission, setting the stage for the professional-focused social networking site to go public.

Though the company does not reveal a price, number of shares, or date for its offering, it does offer insight into its financials. LinkedIn generated $120 million in revenue for 2009, and $161 million through the first nine months of 2010, where it also turned a profit with a net income of about $10 million.

That revenue comes from three sources — advertising, job listings and premium subscriptions. The latter has declined significantly as a revenue source since 2007 (from 53% of sales then to 27% through the first nine months of 2010) while job listings and advertising have become the company’s primary growth areas (41% and 32% of revenue, respectively).

In its filing, LinkedIn notes that Facebook, Twitter, Google and Microsoft are all potential competitors, writing that they “could develop competing solutions or partner with third parties to offer such products.” That said, the company finished 2010 with more than 90 million members, and claims to be adding 1 per second in its filing.

Recently, private trading of LinkedIn shares valued the company at nearly $3 billion. That would make the company’s debut bigger than that of Demand Media, which went public on Wednedsay at a valuation of around $1.5 billion. With Skype, Groupon and potentially Facebook also in the mix of IPO candidates this year, LinkedIn’s offering will be another big barometer for the public’s appetite for Internet IPOs.