The .NET 3.5 Client Profile
One of the cool features we announced for .NET 3.5 SP1 was the client profile. The basic premise was that for developers creating client sides applications (eg addins for Office or WPF), they would need to install the full .NET Framework. Once you took into dependencies, this redist was close to 200MB. The normal redist had many features that a client side developer might not need, like ASP.NET or Workflow Foundation (although you can use Workflow Foundation from the client application). We had from many ISVs that the deployment of the framework can be a blocker.
With this in mind, we created the client profile. Now, when I first read this it said the redist is just 28MB. Cool. Obviously it is just a subset of the full framework but 28MB sounds nice. This week, however, I have been digging into a bit more and there a couple of things to be aware of.
1) There is no offline installer for the "client redist". There is an online installer where you have a bootstrapper that would determine what you need, and then download the client profile if it met the requirements
2) The "client redist" is largely intended for XP SP2 machines
3) The client redist will not install on machines where the full framework is installed.
For more information, check out the Client Profile Explained entry from Jaime.