Yesterday Apple confirmed the much-anticipated announcement of the iPhone 5 slated for Oct. 4th. Today, TechCrunch reports that 41 percent of U.S. mobile users intend to buy the new device, citing survey results from mobile ad network InMobi.

It’s no wonder. Rumors and speculation about the new iPhone have been circulating for months, firing up consumer desire and purchase intent.

A recent study by eMarketer revealed that 63 percent of mobile marketers are either not trying to measure return on investment on mobile campaigns or are not able to evaluate performance at all. This sobering study shows that while the mobile industry has made huge strides in recent years, gauging app marketing effectiveness continues to be a challenge. For many, click-based campaigns are the default metric, however, like the name suggests, they only measure clicks.

Brands are quickly realizing that in order to build sustainable app businesses, it’s going to take much more than just reaching sky-high download numbers. It’s becoming increasingly clear to developers, publishers and marketers alike that forging real relationships with users through ongoing engagement to keep them coming back for more, is critical.

Much has been written in the past month about Apple’s ban on apps that use incentivized downloads to promote other apps. Whether you support Apple’s move or not, there remains one indisputable fact: for advertisers, incentivized networks have been a valuable and cost-effective means of securing app store visibility and downloads; and for app publishers it has been a complementary, high margin revenue stream.