In a keynote address at the recent Mobile World Congress (MWC) in Barcelona, Sir Martin Sorrell, founder and CEO of WPP PLC - the world's leading advertising company by revenue - said that described mobile apps as the "holy grail" of the smartphone industry.

Sorrell highlighted the fact that even though the nascent mobile-advertising industry will get a boost with the growth of bigger-screen tablets and smartphones, the generation of revenue from mobile advertising will still take some time.

Noting that "mobile advertising has definitely gained weight" and that "people are absorbed by it and want to experiment with it," Sorrell said during the course of an interview: "It's still got a long way to go. The problem is, it's highly fragmented."

One of the main obstacles is the scuffle between handset makers and various operating systems; chiefly Google's open-source Android OS, the Apple iOS platform; and Microsoft's Windows Phone 7.

According to Gartner analyst Stephanie Baghdassarian, despite the fact that apps for different platforms are flooding the market scene, advertising inventory - that is, the amount of traffic or impressions which a publisher can sell to advertisers who wish to target users visiting a publisher's site - is too scattered.

Nonetheless, talking about the immense potential in the mobile arena, Naveen Tewari, founder and chief executive of an independent mobile-ad network called InMobi, remarked: "We're at the tip of the Iceberg" in terms of what can be done with mobile.