Hook me up with a license and I'll check. 5.5 does have XML-RPC, and I'd be willing to bet thats how Contribute 4 does it.
It would be really nice if CF supported xmlrpc natively. I'm trying to integrate this into ractorBlog right now and it's not going well because of the reliance on xmlrpc.
OK Ben, could you get us the specs on the interface it uses to hook up to blogs. I would like to build with this interface also. Contribute is a good piece of software and something that clients can handle without a confusion. Thanks for posting this!