注意： 正交的 手段“独立的或分开的”.
蒂姆·奥’Reilly在谈论RSS2.0（简单）和RSS1.0（可扩展）。我最近’ve been thinking 和 reading about weblog 话题s. 的re seems to be the same issues of 简单 vs extensibility in this space too, although nowhere near as much mud-flinging.
“A 话题 map is a kind of index or information overlay which 能够 be constructed 分离 from a set of resources, identifying instances of subjects 和 relationships within the set of resources.”
钥匙 things to note are that 话题 maps are 分离 从实际内容中提取出来的内容，然后将它们组织成主题或类别。尽管XTM仅在2001年创建，但是主题映射可以追溯到1993年，其根源是SGML。正确的是，这个规格是复杂的野兽。 SGML是 like the queen ant of XML (to borrow 可可’s 蚂蚁 metaphor）和 它诞生了 many XML 蚂蚁s.
的 XTM spec is a bulky insect, weighing in at 100 pages long. But being heavy gives it the advantage of extensibility. Using XTM, you 能够 define not only 话题s but also associations, occurances, characteristics, hierarchies, mergers – the list goes on.
XTM even has a fancy term for creating a 话题: 化身。规范将其定义为：
“The act of creating a 话题. When anything is reified it becomes the subject of the 话题 thus created; to reify something is therefore to create a 话题 of which that thing is the subject.”
Riiiiiight。现在我明白了为什么他们使用莎士比亚作为 an example 话题 in the 规格 ðŸ™‚ But it also illustrates that XTM has a lot of scope 和 you 能够 define 话题s for Africa.
“ENT is intended to be a very simple standard for describing how 话题 information 能够 be introduced into an RSS2.0 news feed.”
ENT is a lightweight 蚂蚁, weighing in at only 8 pages. 它只有两个主要概念：“topic” 和 the “cloud”, which is like a map of 话题s. 耳鼻喉科不一定’具有与XTM相同的可扩展性或功能广度。但在这里’的踢腿。耳鼻喉科 参考 XTM. ENT 话题s 能够 be linked to an XTM 话题 map (as well as RDF), via a URI within a 云. Whoa, lotta acronyms in that last 句子。但是重点是，使用ENT along with XTM 手段you get 都 简单性和可扩展性。