All mobile ad networks are growing very fast.

It would be impossible not to be growing very fast in an world that's becoming majority smartphone in the core North American and European markets, as well as growing like gangbusters in China, Brazil, India, Indonesia and Russia.

Still, even in such a market, InMobi has plenty of reasons to be satisfied with its performance.

Currently on 100 billion ad impressions per month, it claims itself as the largest independent mobile ad network, also raising $200 million in mid-2011 to further fund growth.

It's recently opened new offices in Paris Spain, Sweden, Russian, Dubai and China.

"We need to open offices to deal with the local agencies," explains director of business development, Limvirak Chea.

"It's important that we have a global sales team," adding "it not about growth per se, it's about quality."

Best of both

Scale and quality: global and local.

Chea's point is that while banner ads remain the industry's bulk inventory, smartphones are driving the volumes of higher value rich media ads.

But those higher value ad units require closer work with agencies and brands, as well as better tools and processes,

That's something InMobi will continue to push hard in 2012; notably through its acquisition of US HTML5 ad specialist Sprout. It's also looking to buy similar technology providers who could add significant value to its platform

"Sprout provides us with the technology and so the opportunity to push the agencies to use more and better rich media ads, driving the premium ad business," Chea explains.

Two bad Apples?

Of course, quality isn't just about the content of an advert, but also the audience that consumes adverts.

That's one of the reasons InMobi hasn't got involved in offerwalls and incentivised downloads, unlike some of the ad game specialists such as Tapjoy, W3i and SponsorPay.

"It works well but I think it's a short term approach that's reaching its limits," Chea explains.

"It's also very dangerous, as we've seen with Apple [banning it on iOS]. Our plan is different."

As for another obstacle thrown by Apple to annoy the industry - the redaction of device tracking UDIDs - InMobi obviously has plans, but Chea won't talk in detail.

"We care about privacy, we always hash UDIDs, but we like to track at user level," he says.

"We're looking at alternatives and testing them. You have to be ready with an alternative, but we're not saying anything officially at the moment."