The talks have valued Twitter at $8 billion to $10 billion, The Wall Street Journal said, citing unnamed people familiar with the matter. The Journal said the company had 2010 revenue of $45 million but lost money as it hired and invested in data centers.

Investors have shown keen interest in social networking services in recent months. Last month, daily coupon website Groupon raised $950 million in financing after reportedly turning down Google's offer to purchase it for $6 billion. Facebook, which is privately held, is also said to have received $500 million in new funding last month, including $450 million from wealthy Goldman Sachs clients living outside the U.S., and $50 million from a Russian investor.

Also last month, LinkedIn, a social networking site geared toward professionals, filed to go public in an initial public offering worth up to $175 million.

Twitter and Facebook declined to comment. Google did not immediately respond to a message seeking comment.

Google's stock fell $3.08 to $613.42 in afternoon trading.