Recently, there is a flux of new Web Services specifications that are addressing low-level engineering needs, for example the speed of the communication, or even the network protocol. Let's see two of them:
1) SOAP over UDP. The name is self-describing: you send SOAP messages in UDP packets. The funny thing is that an IP address is just a particular case of a more general WS-Addressing address. You can specify an IP address as source/target but also a domain name, etc. The specification is probably a good example that shows how general WS-Addressing can be. Here is an example of a UDP packet:
(001) <S:Envelope xmlns:S="http://www.w3.org/2003/05/soap-envelope" xmlns:wsa="http://schemas.xmlsoap.org/ws/2004/08/addressing" >
(005) <wsa:MessageId> uuid:1da72f1a-5546-493c-934c-a9e3577e206a </wsa:MessageId>
2) MTOM is another specification that allows pure binary data to be sent along with SOAP messages. The same idea appeared in an earlier spec (SOAP with Attachments) but MTOM pushes the concept further by considering optimizations not only at the wire level (i.e. how to efficiently serialize SOAP messages with binary data) but also on the transmission protocol itself.
Interestingly enough, Ricoh and Lexmark contributed to the first specification, while Canon contributed to the second one... I can't wait for the first web-service enabled photo camera!