Mobile ad network Millennial Media has filed for an IPO of up to $75 million. This comes after certain competitors in the space were bought, including Google’s acquiring Admob and Apple’s turning Quattro into iAd.

Millennial says that it is the leading independent mobile advertising platform company with a network reaches 200 million unique users, with 40 billion ads processed in December. It is believed that has 17 percent of the market, making it second only to Admob and unlike Admob or iAd, Millennial isn’t affiliated with a specific operating system or device.

Millennial’s revenue has grown from $6 million in 2008 to $16 million in 2009 and $48 million in 2010, with $69 million during the first nine months. However, the company has never posted an annual profit and expects its expenses to continue to go up.

Worries for potential investors include whether they can take on larger competitors, when and if data collection will be quashed by government regulation or industry standards and a general malaise surrounding tech stocks since LinkedIn went public last year.

Millennial argues that they have a grown collection of anonymized user data and its ability to target specific audiences. The company also argues that its technology platform is “architected to deliver mobile advertising at scale, rather than applying traditional online advertising technology or focusing on a particular mobile operating system.”

Source: AdWeek