Where did PaSSAPI come from?
PaSSAPI started as an idea of Dave Winer, which I stole from him when he didn't pursue further. Dave introduced the idea of Portable and Simple Syndication, which would allow RSS 2.0 element to be used w/in other XML grammars. Originally, Dave called the format PSS. I renamed it PaSS and released version 1.1 last December. PaSSAPI is an API built on top of PaSS.
How did I develop PaSSAPI?
PaSSAPI was developed entirely by writing a WSDL file that described the methods of MetaWeblogAPI and BloggerAPI. The first implementation is entirely in SOAP, but I plan to release an HTTP GET and HTTP POST version in the near future. I may also add methods and welcome suggestions.
Why not just use MetaWeblogAPI?
MetaWeblogAPI uses a great Web RPC called XML-RPC. Unfortunately, I wanted a protocol that worked equally w/ SOAP, HTTP GET and HTTP POST. By allowing use of SOAP, you can actually send PaSSAPI request over alternate transports like SMTP. XML-RPC is bound to HTTP. Also, XML-RPC method calls cannot be expressed in WSDL and I'm pretty upset at Microsoft and IBM for this failure.
Is PaSSAPI competitive to AtomAPI?
Not really. I didn't take the time to incorporate the ideals of Atom into PaSSAPI. If you want to use REST and Atom syntax, then I suggest you continue to use AtomAPI, but if you want a lightweight protocol that works out of the box w/ existing tools, then you might want to consider PaSSAPI.
What do you mean by Works Out-Of-Box?
Any tool that sucks in WSDL can be made to work w/ PaSSAPI in minutes. Trying to do the same in WSDL incompatible technologies takes man-days, if not man-months of effort and is generally bug laden.
What do you mean by lightweight protocol?
By lightweight, I mean that the entire protocol is described in a 400 line XML file and requires very little code to implement.
What is down the road?
First, iM going to listen to the feedback, then I plan on incorporating some of the feedback into the API and finally I will start releasing tools, like C# and Java client and server interfaces.