Twitter turned seven last week. I’m sure millions of 140-character birthday wishes were Tweeted out. There probably are about that many people clamoring for the social media site to go public. With 500 million registered users, Twitter is firmly embedded in the global mainstream. Even the pope had a Twitter account. While that still pales in comparison to Facebook’s (NASDAQ: FB) 1.2 billion monthly users, speculation is running rampant as to when Twitter will follow the social network’s lead in taking its company public. Facebook’s IPO struggles last May could be one reason Twitter has been reluctant to pull the trigger on its own IPO. The current Wall Street scuttlebutt is that a Twitter IPO is about a year away. The thinking is that the company is taking its time, making sure it’s profitable so that it can avoid the same shortcomings as Groupon (NASDAQ: GRPN), Pandora (NYSE: P) and Zynga (NASDAQ: ZNGA) since those social media stocks went public. Economists’ best guess values Twitter at roughly $10 billion right now – a tenth of Facebook’s valuation when it went public. A Twitter IPO is “not necessarily inevitable,” as company CEO Dick Costolo told the Wall Street Journal recently. Still, with rapidly multiplying user numbers and so many people wanting to own a piece of the company they use to connect with the world several times a day, demand for a Twitter IPO is definitely reaching a fever pitch. One hundred forty characters at a time.