Mobile advertising marketplace Adfonic announced Wednesday that it has raised $7.5 million in funding from its existing investors, with telecom entrepreneur and investor Gordon Shields leading the round.

Connecting a wide variety of advertisers and publishers on its mobile ad network, Adfonic says it has seen revenues bloom tenfold in the last year. Its network of sites and apps numbers over 8,000 and it sees over 15 billion ad requests every month.

Several well-known brands run campaigns on Adfonic’s network, including eBay, Google, Groupon, McDonalds and Samsung.

The space is “crowded,” admits Adfonic CEO Victor Malachard, “but there are relatively few ghenuinely [sic] international players. Basically there's Millennial, InMobi, Buzz City and Google - and each is strong in their own region. We're in that company, with a leaning towards Europe. And this is why we've raised more finance, to help us expand. We'll be looking to open in San Francisco, Italy, Germany and South East Asia.”

More generally, Adfonic plans to use its new funding to advance growth in North America, Europe and Asia-Pacific. The company plans to expand its team--in operations, product development, engineering and marketing--from 40 today to over 100 by next year.

Everyone knows mobile advertising to be a rapidly growing space, but just how fast is it growing?

Adfonic cites data from Gartner predicting global mobile ad revenue to reach $3.3 billion in 2011, doubling the $1.6 billion from 2010. In 2015, Gartner has revenue pegged at $20.6 billion. In the U.S. alone, BIA/Kelsey forecasts mobile ad revenues to reach $4 billion in 2015, a more than fivefold increase from the $790 million in revenues seen last year.

Already, marketers have affirmed that they’ll be spending all that extra cash. An IAB survey published in July found that 72 percent of top-level brand marketers have plans to increase ad spend.