Ben,All of your questions are answered in the help. For example, there is a diagram that shows exactly how the BO ties to the DAL which talks to the databases (Application Framework -> Data Access Concepts -> Overview).
The BusinessLayer class is the class which all business objects inherit from. A business object is just an entity with a business layer. A business layer is nothing more than a collection of business objects.
Is Business object simply a collection of rows with methods and events? Is it more like a disconnected memory table?
A business object is the entity which houses all of the logic that interacts with the UI and the DAL. It is the "middle tier" of the application. The business object uses an ADO.NET data table to house all of the disconnected data that is either created or retreived from a server or database. This is only a piece of the data. As for a disconnected memory table...yes. Everything in StrataFrame is disconnected and a BO runs in memory. You can serialize a BO to a stream or to a byte array which then extends the flexibility of a BO to a true memory object it you have the need for serialization or remoting.
What's data tables in relation to Business object?
None other than the BOs use an internal data table that can be reference on each BO through the CurrentDataTable property. I recommend that you read the help article: Application Framework -> Business Layer -> Programmatic Access -> Exposed ADO.NET Components. This will answer the next question as well in regards to a view. This is all covered in the help.