ADO- Connection-Oriented Architecture
     Use Record Set
     Communicate in Binary mode

Ado.net Dis-connected architecture
       Use DataSet,Adapter  
       Parse Data in XML mode

ADO was a connected data access model, which means that when
a connection to the database is made, the connection remains
open until the application is closed.

ADO.NET is disconnected database access model, which means
when an application interacts with the database, the
connection is opened to serve the request of the
application, and is closed as soon as the request is completed. 

All data is presented in XML, as compared to ADO.

The old ADO (ActiveX Data Object) has evolved to ADO.NET in
the .NET Framework. The ADO.NET object is a lightweight
object. The ADO Recordset was a huge object in ADO. It
provided the ability to support multiple types of cursors.
It provided fast lightweight "firehose" cursor and also
supported a disconnected client-side cursor that supported
tracking, optimistic locking, and automatic batch updates of
a central database. However, all of this functionality was
difficult to customize.
ADO.NET breaks the functionality of the ADO object to
multiple classes, thereby allowing a focused approach to
developing code. The ADO.NET DataReader is equivalent to the
"firehose" cursor. The DataSet is a disconnected cache with
tracking and control binding functionality. The DataAdapter
provides the ability to completely customize how the central
data store is updated with the changes to a DataSet.