Twitter Inc, is conducting a new round of private fund-raising that values the company as high as $7 billion, said a person familiar with the matter in a Wall Street Journal report.Seven months ago, the company raised $200 million in a financing round led by Kleiner Perkins Caufield & Byers that valued the company at $3.7 billion.The source did not say what investors are participating in this round of financing.Unlike other fast growing Internet companies, like LinkedIn (NYSE:LNKD), Groupon Inc, and Zynga Inc, the San Francisco based Twitter doesn’t seem to have any plans to go public.The company is currently focusing on building an experienced executive team and creating an advertising business, which it started last year.Twitter is currently on track for approximately $150 million in advertising revenue this year, according to eMarketer, an Internet research firm.