Twitter has filed for an initial public offering with U.S. regulators, the company said on Thursday via a tweet, of course. The company filed for an IPO confidentially under a law intended to help emerging corporations with less than $1 billion in revenue go public.

Twitter has been valued by private investors at more than $10 billion. The company makes money by inserting paid, targeted ads in user-generated content.

Thenews came as a bit of a surprise, as many tech watchers and analysts hadn't expected the company to file until early 2014 at the earliest.

Since more than half of Twitter's revenue already comes from mobile advertising, Twitter's investors should not be as worried as they were when Facebook had filed for its IPO.