The SPSite is a Class which represents a collection of sites and SpWeb is a class which represents a web or subsites. A SPSite class contains the various subsites and the information regarding them.

The SPSite object represents a collection of sites, i.e. Site Collection, a top level site and all its sub sites. - It is used to get a sub site of a Site Collection. - It is represented within an SPSiteCollection object that consists of the collection of all site collections in the Web application. - It contains the various subsites and the information regarding them. SPWeb: - The SPWeb object represents an instance of a SharePoint Web, and the SPWeb object contains things like the actual content. - It represents a SharePoint Foundation website. - SPWeb object automatically adds the new SPWeb object to an internal list. - It contains things like the actual content.