Another day, another move in the mobile advertising space. Now Opera Software says it has acquired AdMarvel, a mobile ad firm based in San Mateo, Calif.

The terms were $8 million now, plus $15 million in cash consideration if certain aggressive financial targets are met in 24 months, according to Opera spokesman Thomas Ford.

In a press release, Opera, based in Oslo, Norway, said the acquisition will expand its portfolio of products and services to include scalable ad monetization services for Opera-branded mobile products and services offered by mobile operators and content partners.

AdMarvel works with carriers and others in the advertising ecosystem to improve the performance of mobile advertising. The company was founded in 2006 by a team of mobile veterans led by Mahi de Silva, a former VeriSign executive who co-founded Frengo.

“In our fast-growing industry, mobile advertising represents an interesting long-term revenue opportunity. Every month, nearly 50 million people access the Web using Opera on their mobile phones and together with AdMarvel, we think we can play an important role in the evolution of mobile advertising,” said Lars Boilesen, CEO of Opera Software, in the press release.

The acquisition follows much higher profile deals involving Google and AdMob and Apple and Quattro Wireless.

According to stats released today by mobile analytics specialist Bango, 83 percent of brands remain in the dark about mobile campaign performance and 27 percent use no analytics to measure their mobile campaigns. Bango surveyed more than 100 participants in a webinar in late 2009, including brands, agencies and specialist mobile providers. More than 90 percent of those brands said they will increase their mobile advertising investment in 2010.