Twitter Headquarters, San Francisco, United States

Twitter raised over US$57 million from venture capitalist growth funding, although exact numbers are not publicly disclosed. Twitter's first A round of funding was for an undisclosed amount that is rumored to have been between $1 million and $5 million. Its second B round of funding in 2008 was for $22 million and its third C round of funding in 2009 was for $35 million from Institutional Venture Partners and Benchmark Capital along with an undisclosed amount from other investors including Union Square Ventures, Spark Capital and Insight Venture Partners. Twitter is backed by Union Square Ventures, Digital Garage, Spark Capital, and Bezos Expeditions.
The Industry Standard has remarked that Twitter's long-term viability is limited by a lack of revenue. Twitter board member Todd Chaffee forecast that the company could profit from e-commerce, noting that users may want to buy items directly from Twitter since it already provides product recommendations and promotions.
On April 13, 2010, Twitter announced plans to offer paid advertising for companies that would be able to purchase "promoted tweets" to appear in selective search results on the Twitter website, similar to Google Adwords' advertising model. As of April 13, Twitter announced it had already signed up a number of companies wishing to advertise including Sony Pictures, Red Bull, Best Buy, and Starbucks.
Some of Twitter's revenue and user growth documents were illegally published on TechCrunch by the hacker Croll Hacker. The documents projected 2009 revenues of $400,000 in the third quarter and $4 million in the fourth quarter along with 25 million users by the end of the year. The projections for the end of 2013 were $1.54 billion in revenue, $111 million in net earnings, and 1 billion users. No information about how Twitter plans to achieve those numbers has been published. In response, Twitter co-founder Biz Stone published a blog post suggesting the possibility of legal action against the hacker.