Thumbs down. He taught an entire course on XML, which he calls a "great meta-example on how to deal with semi-structured data"? And his only defense of XML over JSON is... it's worked ok for some file formats? The only point in this whole article is that XML is not well-suited for RPCs, though he fails to argue that it's well-suited for anything else. One argument is that XML is better than JSON for use cases like XH…
"I get the feeling XML wasn't really made for this case, though, it was made for the JSON-like case." Back in 1997, XML was "SGML for the Web." It was a way to pass around structured, plain-text, human-readable documents that did not require expensive, buggy, incomplete parsers. It then got misapplied as an RPC transport encoding, and tools vendors were more than happy to start pushing specs, such as W3C Schemas, tha…
Sadly there were some sensible early formats that were left behind. XML-RPC's serialization is a bit verbose but otherwise is quite similar to JSON. Somehow that got turned into SOAP and then eventually the WS- tar pit of complexity.
Likewise XML as a configuration file language can be quite elegant, almost like a literate coding version of common .ini or .conf files. But instead of this simple flat document littered with variables, xml config files in the wild end up with deeply nested structure that contributes dubious value and makes the files far less human friendly.
XML itself, with the possible exception of namespaces and a few other features, is quite simple. I totally agree it's the applications that have gotten out of hand, particularly in areas where XML is used as structured data exchange rather than document markup.