RSS 2.0 and Atom 1.0 Compared

＠ Major/qualitative differences

* Deployment
* Specifications

The RSS 2.0 specification is copyrighted by Harvard University and is
frozen. No significant changes can be made and it is intended that future
work be done under a different name; Atom is one example of such work.

The Atom 1.0 specification (in the course of becoming an IETF standards
track RFC) represents the consensus of the　Atompub Working Group
within the IETF, as reviewed and approved by the IETF community and the
Internet Engineering Steering Group. The specification is structured in
such a way that the IETF could conceivably issue further versions or
revisions of this specification without breaking existing deployments,
although there is no commitment, nor currently expressed interest, in
doing so.

* Publishing protocols

* Required content

RSS 2.0 requires feed-level title, link, and description. RSS 2.0 does
not require that any of the fields of individual items in a feed be
present.

Atom 1.0 requires that both feeds and entries include a title (which may
be empty), a unique identifier, and a last-updated timestamp.

* Payload

RSS 2.0 may contain either plain text or escaped HTML, with no way to
indicate which of the two is provided. Escaped HTML is ugly (for example,
the string AT&T would be expressed as “AT&T”) and has been a
source of difficulty for implementors. RSS 2.0 cannot contain actual
well-formed XML markup, which reduces the re-usability of content.

Atom has a carefully-designed payload container. Content may be
explicitly labeled as any one of:
○ plain text, with no markup (the default)
○ escaped HTML, like is commonly used with RSS 2.0
○ well-formed, displayable XHTML markup
○ some other XML vocabulary
○ base64-encoded binary content (again, no guarantee)
○ a pointer to Web content not included in the feed

* Full or partial content
* Autodiscovery
* Extraction and aggregation

＠ Differences of degree

* Extensibility

RSS 2.0 is not in an XML namespace but may contain elements from other
XML namespaces. There is no central place where one can find out about
many popular extensions, such as dc:creator and content:encoded.

Atom 1.0 is in an XML namespace and may contain elements or attributes
from other XML namespaces. There are specific guidelines on how to
interpret extension elements. Additionally, there will be an IANA managed
directory rel= values for . Finally, Atom 1.0 provides recommended
extension points and guidance on how to interpret simple extensions.

* URIs
* Software availability
* Language tagging
* Digital signatures and encryption
* Authors
* Categories
* Schema

The RSS 2.0 specification includes no schema.
Atom 1.0 includes a (non-normative) ISO-Standard RelaxNG schema, to
support those who want to check the validity of data advertised as
Atom 1.0. Other schema formats can be generated from the RelaxNG schema.

＠ Sample RSS and Atom Feeds

RSS 2.0 (687 bytes)





Insert witty or insightful remark here
http://example.org/
Sat, 13 Dec 2003 18:30:02 GMT
johndoe@example.com (John Doe)



http://example.org/2003/12/13/atom03
isPermaLink=""false"">urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a
Sat, 13 Dec 2003 18:30:02 GMT
Some text.






Atom 1.0 (677 bytes)




Insert witty or insightful remark here

2003-12-13T18:30:02Z

John Doe
johndoe@example.com

urn:uuid:60a76c80-d399-11d9-b93C-0003939e0af6




urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a
2003-12-13T18:30:02Z

Some text.

Reference:
http://www.intertwingly.net/wiki/pie/Rss20AndAtom10Compared