Twitter Inc, yesterday raised $200 million in a new round of funding from investors, valuing the micro blogging website of 140 characters at $3.7 billion.

The new round of fund raising led by venture capital firm Kleiner Perkins Caufield & Byers has seen the company's valuation jump by $2.7 billion from last year, when it raised $100 million in September valuing it at $1 billion.

The whopping valuation comes despite the company nit yet having make profits being in business for the past four years.

The funding also bought in two new board members, Mike McCue, founder of social magazine application Flipboard, and David Rosenblatt, former CEO of DoubleClick, a subsidiary of Google that develops and provides Internet ad serving services.

Twitter said in a blog post, ''As part of a significant new round of funding with investor Kleiner Perkins Caufield Byers and existing investors, we've added two new members to Twitter's board of directors. Please join us in welcoming Mike McCue and David Rosenblatt. The experience these new directors bring to Twitter, along with this renewed investment, will help us continue to grow as a company and business.''

San Francisco-based Twitter now has eight directors on its board and added 220 employees last year taking its total staff strength to 350.

The tweeting phenomena, which has more than more than 175 million registered users, allows users to pepper one another with messages of 140 characters or less. It has grown rapidly in popularity since it was launched in August 2006 but has been unable so far to generate revenue.

Twitter allows users to post short updates on anything from their latest date to their views on any interesting news item. The service has emerged as a valuable source of information and news, which users can access from mobile devices or personal computers.

The company, founded by CEO Evan Williams with partners Biz Stone and Jack Dorsey, had rejected an offer to sell itself to Facebook Inc in 2008, (See: Facebook's take-over talks with Twitter break down) and was also reportedly a target by Google last year. (Also read: Why Google tweeted Twitter)

The company, which has now raised about $360 million from venture firms including Benchmark Capital and Union Square Ventures had said last year that it would begin building revenue-generating products.

Recently it allowed 'sponsored tweets', where advertisers pay money to send out messages, and more than 80 brand like Coca-Cola and Verizon Wireless are paying around $100,000 for the service.