Firstly, thanks to everyone involved in getting back this site.  Fortunately, I didn't have too much to lose but now the lesson's learnt I will be happier to build up a bigger collection of clippings in this blog.

What follows is a nice set of bullet points describing the logical architecture of MOSS 2007.  The definition of a Top-level Site is welcome.  They are a special kind of site and I'd been calling them "the root level site" but now there is a defined term we can all understand each other.

•  Server farm or single server deployment: The top-level design construct of a Windows SharePoint Services infrastructure is a stand-alone or server farm deployment of Windows SharePoint Services. A stand-alone installation includes Windows SharePoint Services and Microsoft SQL Server® on the same server. A server farm allows the separation of application and database server roles. An enterprise can support one or more Windows SharePoint Services farms. You administer each server farm as a unit from the shared administrative tools in the server farm’s SharePoint Central Administration site.
•  Web application: A Web application is a logical component that is associated in a one-to-one relationship with a unique Microsoft Internet Information Services (IIS) Web site. You use the server farm’s SharePoint Central Administration site to manage Web applications.
•  Site collection: A site collection is a component that encompasses one or more Windows SharePoint Services sites. You manage some features of site collections by using SharePoint Central Administration, and you manage others from the Site Settings page of the site collection’s top-level site.
•  Site: Within a site collection, you can create one or more Windows SharePoint Services sites.
•  Top-level site: The top-level site within a site collection is the site with the URL of the site collection itself. Top-level sites define certain configurations, such as features and templates, that affect all sites within the site collection.
•  Lists and libraries: Lists and libraries are basically the equivalent of data tables in a database application. Whereas lists can support document attachments, libraries are a type of list in which the document is the focal point, and columns in the list provide metadata about the document.
•  Items and documents: The records in a Windows SharePoint Services list are called items. A library is a list that contains documents.