Google has just released a beta version of a tool called App Inventor for Android that lets you "build just about any [Android] app you can imagine." Similar in function to early versions of Visual Basic, this is a serious competitive threat to iPhone, Windows Phone, and other smart phone platforms, while harkening back to the early days of the PC, when people were often expected to make their own applications. I haven't tried it yet (I'm on a train to New York as I write this), and it has some weird system requirements, but it looks impressive.

App building is not limited to simple games. You can also build apps that inform and educate. You can create a quiz app to help you and your classmates study for a test. With Android's text-to-speech capabilities, you can even have the phone ask the questions aloud.

To use App Inventor, you do not need to be a developer. App Inventor requires NO programming knowledge. This is because instead of writing code, you visually design the way the app looks and use blocks to specify the app's behavior.

The App Inventor team has created blocks for just about everything you can do with an Android phone, as well as blocks for doing "programming-like" stuff-- blocks to store information, blocks for repeating actions, and blocks to perform actions under certain conditions. There are even blocks to talk to services like Twitter.

Because App Inventor provides access to a GPS-location sensor, you can build apps that know where you are.

You can write apps that use the phone features of an Android phone. You can write an app that periodically texts "missing you" to your loved ones, or an app "No Text While Driving" that responds to all texts automatically with "sorry, I'm driving and will contact you later".

App Inventor provides a way for you to communicate with the web. If you know how to write web apps, you can use App Inventor to write Android apps that talk to your favorite web sites, such as Amazon and Twitter.

Impressive.