In MOSS 2007 we have two main things and they are
1.Administrative part
2.WSS object model for customizing the sharepoint pages

With administrative previleges one can create(delete) and many more operations. Specially for the customization of sharepoint pages we use Windows Sharepoint Services 3.0 object model.
In the front end web server we have virtual directory which has different folders created under the path as c:\program files\common files\microsoft shared\web server extensions\12\bin known as system directory. Under the system directory inside the bin folder we have stsadm.exe which is a command line utility for creating new site collections and used for activating and deactivating the features. Features provide a mechanism for defining site elements and adding them to a target site or site collection through a process known as "feature activation".