Four out of five mobile developers either build apps for the iPhone or are planning to do so, according to market researcher Ovum. This, however, doesn't mean other mobile platforms, such as RIM's BlackBerry OS or Microsoft's Phone OS, are falling by the wayside.They're feeling the love from developers, too.Ovum surveyed 217 mobile app developers and found that all five mobile platforms\u2014iPhone, BlackBerry, Microsoft, Android and Symbian\u2014fared well. Of course, the iPhone, which basically created the mass market for mobile apps, leads the way: 81 percent of respondents say they are developing or planning to develop on the platform. The App Store serves up more than 185,000 apps.BlackBerry OS followed with 74 percent, along with Windows Phone OS (formerly Windows Mobile) with 66 percent, Android with 66 percent, and Symbian with 56 percent. Only 30 percent of developers said they would support other platforms, such as LiMo and Palm's WebOS.BlackBerry's strong showing bodes well for embattled mobile phone vendor RIM. "These results will be most gratifying for RIM, which appears to have successfully made the transition from enterprise-centric applications and can now be considered mainstream," writes Ovum analyst Tony Cripps in a research note.Microsoft should also feel good about the results, notes Cripps, as the software giant readies Windows Phone OS 7.0. "This support for Microsoft smartphones is, we believe, reflective of the company's eminence as a tools vendor, if not necessarily the user friendliness of its device platform."Meanwhile, Android's lackluster position may seem surprising, given all the hype that has surrounded the platform. Yet Android is also the most recent of the five OSes to hit the market and thus has a relatively small installed base, notes Cripps.Mobile app developers play a crucial role in the success of mobile devices, including the emerging tablet market. They might, in fact, be the decisive factor in determining future winners and losers. "The user experience as defined by user interface and the services and software that are delivered on the device is what matters," says Gartner analyst Van Baker.One of the reasons all five mobile platforms posted good numbers in Ovum's survey is because developers, like ever-calculating traders on Wall Street, hedge their bets. That is, they're creating apps across multiple platforms.Apple, however, has spurred cross-platform development in the mobile space with its reckless treatment of developers, say some developers who were caught up in Apple's surprise raid on apps with explicit sexual content earlier this year. (Never mind that Apple had already approved these apps.)"I was one of the many developers who was making thousands of dollars a month from bikini apps for the iPhone," laments Mark Greenfield, developer of iPhone app Bikini World, whose business was destroyed overnight. "Our best downloaded app was Bikini World Lite with over 800,000 downloads."Gerrard Dennis, CEO of The Simply Group, a U.K.-based online retailer, also saw his iPhone women's swimwear retail app suddenly disappear from the App Store. Worried that a good piece of his business may be wiped out, Dennis called Apple for help\u2014and his pleas were met with silence.Dennis' swimwear app reappeared on the App Store four days later. "Apple's cavalier behavior is not helpful," he says, adding, "we will now explore other platforms as a safety net against this sort of thing happening again, either deliberately or otherwise."Tom Kaneshige is a senior writer for CIO.com in Silicon Valley. Send him an email at firstname.lastname@example.org. Or follow him on Twitter @kaneshige. Follow everything from CIO.com on Twitter @CIOonline.