Here's my take
Dave Winer: an essay to kick off the new year
Dave and I see some of the same data, but we interpret it differently. Here's my take.
Where interfaces are of the simple client/server kind, and where all the state is on the server, the trend I see for the future is that new interfaces will increasingly be defined as a simple HTTP GET.
When there is a wide range of clients implementations, some developers may choose to transcribe this document into machine readable forms, like XML schema and/or RELAX NG so that both static and dynamic bindings can be automatically generated for a wide range of programming environments. When there is a wide range of server implementations, others may write validators using tools as simple as XML parsers and regular expressions to ensure that the there is consistency, conformance to the specifications and that best practices are encouraged.
When there is anticipation of a wide range of clients or servers, then the protocol will be defined to be extensible so that it can be adapted to a wide range of purposes.
RSD is an example of such an interface that has started out along these lines. RSS 2.0 is an example of such an interface that has recently converged onto a similar path.
When the interfaces are simple client/server, but where most or all of the state is on the client, the trend I see for the future is that new interfaces will increasingly be defined as a simple HTTP POST. Human readable docs, and optional machine readable docs, validators, and extensibility characters will also be factors, for much of the same reason.
The TrackBack Specification and RSS validator SOAP interface are both examples of this.
The most important of the non-simple client/server interactions is one of alerts or notification. All sorts of DigID information will need to be added to the data in order to traverse the gauntlet of gateways required.
Once again, the data will be well formed XML, with docs of both human and machine readable forms, and with validators and extensibility provisions.
Once this is in place, polling mechanisms for things like RSS will be replaced with something a bit more bandwidth friendly.
After that, there are still more interesting usage scenarios to consider.