Twitter isn't in the same hurry to go public with a stock offering as other Internet companies, including Groupon, LivingSocial and Zynga.

Those companies have filed paperwork with the SEC to go public, while Twitter, the fast-growing Internet messaging service, is raising private funds for continued operations instead.

The Wall Street Journal reported Tuesday that Twitter is raising hundreds of millions of dollars in a new financing round that values the company as high as $7 billion.

Twitter lets people broadcast and read Internet messages coined tweets. Some industry watchers suggest Twitter could be under attack from Google's new social media product in field market testing now, but Google+ has not been released to the public yet.

A Twitter spokesman declined comment.

Groupon is marching fast toward an IPO. The company filed paperwork with the SEC to initiate the process on June 2, with plans to raise $1 billion. Typically, 60 to 90 days is the minimum time frame to reach public stock tradiing once such paperwork is filed, meaning Groupon's IPO is still another two to three months into the future but the process is underway.

LivingSocial, the second largest web-based daily deals company behind Groupon, met with bankers last week to finalize plans for its planned initial public offering, anticipated to value the company at between $10 billion to $15 billion. 

Both companies are viewed as hurrying stocks to public trading while they are in a fast growth mode at a time technology IPO's have been hot on Wall Street. Professional connection site Linkedin Corp recently went public as did web-based music services Pandora Media Inc. Linkedin priced at the top of its anticipated price range when the stock began trading, while Pandora priced above its expected price range - and both launched publicly within the past 60 days.

Also, Zynga filed for its IPO on July 1. The social games developer has hundreds of millions of active monthly users who purchase virtual goods, valuing the company at an estimated $10 billion to $20 billion.

San Francisco-based Twitter is taking a different approach, however -- remaining a private company into the future as the private capital raising is apparently in lieu of a public stock offering.

The company is reportedly on track to generate about $150 million in ad revenue this year, according to research firm eMarketer. Previously, Twitter raised $200 million in a financing round led by Kleiner Perkins Caulfield & Byers that valued the company at $3.7 billion.

The company's microblogging and social networking service, with text-based posts of up to 140 characters, was launched in July 2006. Five years later, Twitter has 200 million users generating an estimated 200 million tweets a day and processing 1.6 million search engine queries per day.