James Snell points to this developerWorks article by Nick Case which shows how to encrypt and sign Atom entries using Apache Abdera; Pete Lacey correctly notes that this addresses RESTful HTTP’s perceived message-level security shortcoming (and also shows how to use WSS authentication).

As Mark Baker put it a while ago:

For what it’s worth, I believed until quite recently that SOAP was salvageable as a generic XML envelope. But I think Atom has quietly usurped that role while SOAP was distracted being used for RPC.