Google loves to characterize Android as open, and iOS and iPhone as closed, we find this a bit disingenuous and clouding the real difference between our two approaches. The first thing most of us think about when we hear the word open is Windows, which is available on a variety of devices. Unlike Windows, however, where most PCs have the same user interface and run the same app, Android is very fragmented. Many Android OEMs, including the two largest, HTC and Motorola, install proprietary user interfaces to differentiate themselves from the commodity Android experience. The users will have to figure it all out. Compare this with iPhone, where every handset works the same.

Twitter client, Twitter Deck, recently launched their app for Android. They reported that they had to contend with more than 100 different versions of Android software on 244 different handsets. The multiple hardware and software iterations present developers with a daunting challenge. Many Android apps work only on selected Android handsets running selected Android versions. And this is for handsets that have been shipped less than 12 months ago. Compare this with iPhone, where there are two versions of the software, the current and the most recent predecessor to test against.

To date, we've had 36,427 active beta testers, and below you can see the massive variety of phones and Android OS versions everyone is running. We were really shocked to see the number of custom roms, crazy phones and the general level of customization/hackalicious nature of Android. From our perspective, it's pretty cool to have our app work on such a wide variety of devices and Android OS variations.

In reality, we think the open versus closed argument is just a smokescreen to try to hide the real issue, which is, what's best for the customer, fragmented versus integrated. We think Android is very, very fragmented and becoming more fragmented by the day. And as you know, Apple's provides the integrated model so that the user isn't forced to be the systems integrator.

...And we also think our developers can be more innovative if they can target a singular platform rather than a hundred variants. They can put their time into innovative new features rather than testing on hundreds of different handsets.

For a phone OS, it's as open as they come, by a huge margin. Source code is readily available for free download by anybody. Having a complete copy of the source code makes development easier. But in general, you can do anything you want on Android.

Here's where Steve's right: anybody can build their own Android device based on the resources available on-line. If you use Qualcomm chips, Qualcomm will have already written the kernel drivers for you and gotten it all integrated. Other chip vendors probably do the same thing. But if you want your device to work with the DRM-protected apps on the Android market, you have to have your device locked down security-wise and vetted by Google. Sometimes vendors push an over-the-air upgrade and forget to vet the new OS with Google first. Then all of a sudden paid apps stop working. Still, with Android you can generate a single binary that runs everywhere. Yes, there are version issues. Develop for 2.1, then 1.5 phones can't use it. That's why I always develop my apps on the most primitive version of the OS that will run them. The development environment (Eclipse) lets you do that. You can run any version of the OS under the emulator. And every app can specify a version of the OS it was intended for, plus a range of OS versions that it supports.