Because the use of Java is increasing, in websites or software, that is why I install Java Runtime Environment (JRE). Why need JRE? Because the software developed by using Java language will need the JRE, so that the software is WORA (Write Once, Run Anywhere).
Then, Microsoft also produces similar product. That is .NET Framework. .NET Framework becomes popular because of C# language.
However, what I want to say is, I just found that .NET Compact Framework is different from .NET Framework. Now, .NET Framework 3.5 is released. However, the full installation file is about 100mb. It is quite wasting time to download it. And I just found .NET Compact Framework 3.5, which is much smaller than .NET Framework. So, I thought it is a “compact version” of .NET Framework. And search the Wikipedia about .NET Compact Framework, and found that both are different things. 🙂