New URL for code explanation

Apr 20, 2009 at 8:42 PM was obtained by Microsoft.  You can find an archive of Nishil's explanation here instead:

The title is "Creating Custom File Receive Adapter (BizTalk Server 2004)-For Beginners Only" and the first line is "Well, I was searching for documents to create a custom adapter but didn't succeed, so I thought I'll create one."  I figure those two lines will answer most questions about "what is this (for)?"  I'll also add Nishil's disclaimer: "The only intention of this document is to get friendly with Adapters."

Nishil makes use of the BizTalk Server Adapter Wizard, which is also hosted on Codeplex now.

And, of course, the SDK for BizTalk 2006 gives you sample code for creating a custom adapter.