Cocoa Plugins

What is the difference between a Cocoa plugin and an XML plugin? Obviously one is XML and the other is some sort of binary, but why would a Cocoa plugin be necessary, and is there a way to create them?

thanks

A Cocoa plugin can do other sophisticated things that you can’t achieve with an XML plugin.
And, like the scanners you asked about in another post, there are no plans to make the API publicly available at this point in time.