Why did Microsoft produce a new .NET Framework client installer?
Increasingly, client applications are delivered over the Internet. Although Windows Vista includes .NET Framework 3.0 enabled by default, many users are still running Windows XP machines that do not have any .NET Framework installed. Our customers have been very vocal about the need for a smaller, more reliable setup experience. The new .NET Framework Client Profile Preview is designed to make it as easy as possible to acquire the smallest set of files necessary to run a typical client application today.