For years, the Android smartphone operating system stood as the neglected stepsister aside the iPhone’s radiant, beloved iOS. Tens of thousands of suitors--app developers including large corporations and rising creative talents--hurried first to build something for iOS phones. Only belatedly, if at all, would they build something for Android devices.
Today, like the once-dejected heroine, Android is the belle of the ball, with developers as her Prince Charming. They have realized that Android is now at least as important as iOS--and sometimes more so.
Here’s what changed: Android smartphones have become the most popular in the U.S., by a long shot. According to a September 2011 Nielsen study,  40% of all smartphones in the U.S. run Android, vs. 28% for iOS (most of the rest are using RIM’s BlackBerry OS). The study also shows Android leading iPhones as the type that consumers want to get in the future.
Beyond market share, tech teams and business owners find the whole process of making and releasing an Android app easier and quicker--from coding to launching and making money.
Companies are also taking a closer look at their customers. “I believe the Android users are more hardcore than the iOS users,” said Gary Gattis, CEO of mobile game developer Spacetime Studios . Those “hardcore” customers are the ones playing Spacetime’s massively multiplayer 3-D online games.
Spacetime launched its first title, Pocket Legends, on iOS in April, 2010. Despite a seven-month lag for the Android version, the split between users is already 50/50. For its newest title, Star Legends  (released in August), Spacetime went with Android first.
Android appeals to Spaectime’s target demographic: men and women 18 to 29 years old. Their iOS users are much younger--boys from 13 to 18, many playing on a parent’s iPod touch. The kids may be equally passionate, but they don’t have credit cards to purchase in-game upgrades. Given these benefits for game companies, it’s not surprising that they are among the biggest proponents of Android.
Android also propelled sales for Tapjoy , a tech company that enables app makers to offer free content in exchange for some task to be completed by their app users. To get features like new weapons in a game, for example, or additional messages in a free texting app, users might watch a Ford commercial, sign up for Netflix, or install and use the Bing search app.
According to Tapjoy’s CEO, Mihir Shah, Android users take up these offers over twice as often as those on iPhones. One obvious reason: Apple banned pay-per-install apps in April, taking away a big chunk of what Tapjoy can offer to users of iOS apps and devices.
Despite these trends, why do some companies remain fixated on the creation of iPhone apps, and nothing else?
Piracy is one downside. Without the strict policing of Apple’s App Store, the anything-goes Android Market makes it easy for pirates to simply download an app and with a few minor tweaks, re-upload it as their own product. According to a recent Yankee Group study,  these piracy issues can put a dent in the profitability of an Android app, too.
In addition, the market situation has only changed recently. Research firm comScore found iOS phones had a bigger market share until around November 2010, when Android began shooting past. Businesses may be catching up, still.
It can take as long as six months to design and build a complex app of any kind, says Alex Harrington, CEO of location-based dating service MeetMoi , which launched first on Android (and which FastCompany.com previously covered here ). Many companies started when iOS was the clear choice. The market changed while their app was in the shop.
Sometimes the lifestyle of the app-makers holds sway. Take Miso, a social TV app  that allows people to, among other things, see what their friends are watching. “The thing about our platform is, it’s something that we can use ourselves,” said CEO Somrat Niyogi. “Let’s look around our entire office at what people have: iOS, iOS, iOS.”
Like many app makers, Niyogi says that Miso must now give iOS and Android equal attention. "We had this bad history with Android where it was a second-class citizen,” said Scott Lahman, CEO of Gogii, maker of the popular free-texting app Text Plus . “And [now] it could turn out that Android beats iOS for some features." The app’s new voice notes feature and Facebook integration, for example, is debuting in the Android version.
Developers’ device and OS bias can work in Android’s favor, too. “More recently and for a couple of reasons we are seeing a clear and significant case of developers going to Android first and possibly even avoiding iOS altogether,” said Brad Spirrison, managing editor of app-review site Appolicious .
Localicious (which spun out from WhitePages.com) is a provider of tips on popular venues in major U.S. cities. The Android version of Localicious  debuted on July 13, and two updated versions have already followed. The company has yet to provide an iOS version of its app.
Company spokesperson Liz Powell explained in an email: “Currently, we don’t have a firm timeline for launching Localicious on iOS since we have some additional Android projects, one being the Localicious tablet version, that are higher priority in the interim.” Localicious can churn out new versions so quickly because no approval is needed to put them in the Android Marketplace.
According to Gary Gattis of Spacetime Studios, getting the App Store's stamp of approval can take from one to as many as six weeks. Android revisions can go up instantly. MeetMoi’s Alex Harrington compares it to upgrading a website.
While that fact of the Android apps ecosystem isn’t always great for users, who can get a lot of crummy software (and malware) from some Android app stores, it’s great for developers. For one, they can plan on, control, and promote their official launch date when it comes to Android apps. That was a big factor for Localicious. It's also impossible with iOS apps, because Apple isn't in the habit of making guarantees as to when an app will gain approval and move into the store.
Spacetime Studios set its much-anticipated launch of Star Legends, a sci-fi genre multiplayer online game, for August 8 on Android. It didn’t offer the iOS App Store its game until August 25, though. The delay gave Spacetime a chance to refine their game. Not only does Apple have a sometimes-long approval process for any app, it must also approve every modification to the app. “These games are very complex,” said Gattis. “And the probability [that there will be] bugs on [a first] release is huge.” With Android, Spacetime could release updated versions until their game was sufficiently tweaked and refined. They sent the iOS version to Apple, later.
The main reason for Android’s rise is basic math, in the end: Android apps get into the market quicker, where more people can try or buy them.