Nuget vs. Web Installer. How is it related to VS 2010 extensions

Does the functionality of th开发者_如何学Goese overlap ? I understand web installer adds pieces to VS2010 and nuget does also..

How are these related to vs2010 extensions that are NOT allowed in vs2010 express. But nuget is allowed in vs2010 express and that seems to allow extension in the vs2010 express.

Can anyone clear this up for me ?

Nuget is for adding packages or libraries to your current "project" (project meaning general code project not vs proj file). The extension Gallery is designed to extend the functionality of Visual Studio. For instance Nuget Package Manager is in the VS Extension gallery as it extends Visual Studio and adds the ability to add package to your project.