One of the cool new features in introduced in Delphi XE is a possibility to use TObject-descendant as parameter types in DataSnap server methods. I was planning to cover different possible parameter types that you can use in DataSnap applications, but it would be a huge discussion. Jim Tierney from Embarcadero has already discussed different DataSnap parameter types on his blog and during recent CodeRage5 conference session "DataSnap: Features and Integration with User Types".
In Java Enterprise Edition (JEE) there is a concept of “Plain Old Java Object” (http://en.wikipedia.org/wiki/Plain_Old_Java_Object) for passing data between applications. Here we are going to use the same pattern for exchanging data between clients and servers written in Delphi, so it should be OK to call these parameter types: “Plain Old Delphi Objects” or in short “PODOs”.
"Delphi Labs: DataSnap XE - Parameter Types and PODOs"