Millennial Media is seriously considering an IPO. Experts believed that the recent appointment of Jim Tholen as the new board member is the green light that the company is waiting for before they head towards a public offering. Tholen is the second member of the company’s board outside of the VC community and is currently the Chief Finance Officer (CFO) of Broadsoft, a frontrunner of the IP technology and a known global innovator of both residential and business VoIP or Voice over IP for more than e decade now. It was known to many that Tholen brought Broadsoft to IPO last June 2010.

Taking on a role as the largest remaining independent mobile advertising network in the US, Tholen expressed nothing but graciousness and delight saying, “Throughout my career I have had the good fortune to serve a variety of high-growth companies offering innovative applications in emerging markets. I have been impressed with Millennial Media’s growth trajectory, industry leadership, and management team. I am looking forward to the opportunity to serve on Millennial’s Board as they drive to become the critical revenue supplier for mobile application and media developers.”

According to Millennial Media’s CEO Paul Palmieri, Jim will bring with him years of extensive financial experience and strategic expertise. He also noted that the organization is unexpectedly growing at a rapid pace. In April, Millennial Media announced it will grow its current manpower to 50%. Many expected then that the company is heading to IPO and solidifying its base before moving that direction.

Earlier this year, Millennial Media made remarkable impressions when they raised  $27.5 million in additional funding last January via Series A, boosting their finances to a total of $65 million—300% growth from their 2010 revenue. This development earned them a position at the top 3 just behind the giants, Google and Apple.

With almost everything set and beefed up to go public, the only question that remains now is when?