新データ・フォーマットRSD

新たなデータ・フォーマットであるリアリー・シンプル・データRSD。jsonxmlで充分と思われるかもしれないが、提案者によればこれらのフォーマットにはまだまだ改善の余地があるとしていて、RSDはCSSのように人間に読みやすくCSSより豊かな表現が出来る、xmlやdomと同様の基本構造を持つがxmlより軽量である、RSDは比較的簡単にパースでき、xmlyamlに比べると文法が非常にシンプルである点などのRSD導入の利点を挙げている。

Why another data format? Aren't JSON and XML enough? Well, in a word, yes. They all work fine for many applications. So we don't really need another data format, per se. However, I felt there was enough room for improvement to go ahead and make the jump to RSD.
Human Friendly. The simpler the grammar, the more likely that non-technical people will be able to use it. This makes it possible to use RSD as a meta-data format, much like CSS, except that RSD is much richer than CSS.
XML And DOM Friendly. RSD has the same fundamental structure as XML and DOM. It returns a parse tree, rather than specific data structures. As with many XML libraries, RSD can be easily mapped by convention into language and domain specific data structures. And it can also be used as a lightweight, more readable alternative to XML.
Programmer Friendly. RSD is relatively easy to parse or generate because the grammar is simple. It is much simpler than XML or YAML, which will hopefully encourage implementors.

http://dev.zeraweb.com/rsd-initial-announcement/