In a previous post, The 3 Buttons of Windows Phone 7 Series, I talked about the 3 required buttons at the bottom of every Windows Phone 7 device: Back, Windows, and Search.

Now there are rumor leaks of new Dell phones: Flash, Thunder & Lightning. But what do their buttons reveal?

According to Engadget and pocketnow.com, the Dell Flash will run the Android Froyo OS. The posted image shows 3 buttons that might be similar in functionality to the 3 Windows Phone 7 buttons:

Another phone leaked to run the Android OS is the Thunder and its buttons match the icons on the Flash:

The Lightning icons more closely match what you might expect on a Windows Phone 7 namely the Windows button and the Search button:

It is interesting that the 2 Android phones have 3-button designs. The first appears to be a Back button and the second a Home button. On the Windows Phone 7, the third button is Search which will bring up Bing. The Android phones’ third button appears to be a Menu button although some could argue that it represents search results.

Why has Dell chosen to have 3-button designs on phones for two different operating systems that mostly do the same thing?  I wonder how Microsoft feels about this dual usage of the 3-button design?