TWITTER, THE microblogging website that lets users “tweet” messages of 140 characters or less, is now worth $8 billion.

The firm’s new price tag comes after a $400 million investment in the loss-making venture from serial social media investor DST Global.

Twitter is now nominally worth about the same as rating agency Moody’s, which had revenues of $1.2 billion in the first six months of 2011.

The huge valuation reflects high expectations for the company. Confirming the investment, Twitter also announced its users now send 200 million tweets a day, up from 65 million a year ago.

“We have the opportunity to expand Twitter’s reach with a significant round of funding led by the venture firm DST Global, with the participation of several of our existing investors,” Twitter said in a blogpost.

“We will use these resources to aggressively innovate, hire more great people and invest in international expansion.”

The new funds are part of $800 million Twitter wants to raise as it grooms its business for a potential initial public offering. DST Global is led by Russian billionaire Yuri Milner.

Twitter is believed to be using half the money to buy back shares from employees and backers. – (Copyright: Guardian News Media 2011)