Click-to-Run isn’t a new Office “product”. Instead, it is a new way of delivering and updating the programs you’re already familiar with. It has full language support and will work on both 32-bit and 64-bit operating systems, although only the 32-bit version of Office 2010 can actually run on both platforms. It is optimized for home users on broadband connections (at least 1 Mbps).
Here are some reasons to use Click-to-Run:
Programs delivered via Click-to-Run execute in a virtual application environment on your computer. This means that the programs have private copies of their files and settings, and that any changes they make are captured in the virtual environment. The effect is they don’t end up modifying any other applications installed on your computer. With few exceptions, only user data actually passes through the virtual environment to your computer.
Click-to-Run programs also support streaming. Think of this in the same way you think about streaming video. You get to watch the first part of the video before the entire file downloads. With Click-to-Run, you can start using your Office programs before the entire edition or program has been downloaded, so you can get to work much faster. While a program from Click-to-Run is running, the rest of the programs are being downloaded in the background. The initial installation process is very different than what you might be used to. The experience of getting Office Click-to-Run is more like downloading a large web control than doing a traditional Office installation.