Android is Google's mobile and tablet operating system. Many of these are touch screen applications. In the next year or two there is predicted to be an explosion of Android based devices on the mobile phone and tablet platforms. Without having to have approval for applications like on the iPhone, it's expected that there will be quite a few applications available.
For Ubuntu users this is good news. While Ubuntu is not Android by any means only sharing the Linux kernel as a base, there is work being done right now to make sure that Android applications will run on the Ubuntu distribution. Eventually this might be able to work on a number of distributions.
Why this is good is that there is quite a bit of commercial development being made for Android. Some of these are paid applications but many are free. What this means for the Ubuntu user is that there will be a wide variety of new applications that could be used on the system. Some of these specifically made for the phone platform might not be too useful, but those made for tablets can be used on the desktop environment since they are made for larger screens.
Another benefit to this is that if there are great applications made on the Android platform, other developers on distributions that might not be able to run Android software might develop open source versions of the most popular software giving everyone quite a few more beneficial applications to work from whether you use Ubuntu or not.