RSS 0.91 Spec, revision 3 (Netscape's Original
Files must be 100% valid XML. We're trying to
move towards a more standard format, and to this
end we have included several tags from the popular
<scriptingNews> format. We have also ensured
that this version is 100% valid XML. We did this
by requiring that a DOCTYPE tag be included, and
validating each RSS document against that DTD. This
means that it is not enough for an RSS document
to be "well-formed". It must also be "valid" with
respect to its DTD.
No mixed content tags. We are specifically not
including any tags that contain mixed content in
RSS 0.91. This means that each tag either contains
sub-tags only, or text only, not a combination.
This is both because we want to keep the format
simple, and because our current validation system
is not able to handle this type of tag. We also
are not allowing any HTML markup beyond the commonly
used entities such as " A full list of
these are defined in the RSS 0.91 DTD.
New tags for syndication community. Our validator
will now allow several new tags through the system,
though most of them will not actually be used by
Netcenter. However, these may work when syndicating
content to other sites. These tags are noted explicitly
in the spec as "ignored."
RDF references removed. RSS was originally conceived
as a metadata format providing a summary of a website.
Two things have become clear: the first is that
providers want more of a syndication format than
a metadata format. The structure of an RDF file
is very precise and must conform to the RDF data
model in order to be valid. This is not easily human-understandable
and can make it difficult to create useful RDF files.
The second is that few tools are available for RDF
generation, validation and processing. For these
reasons, we have decided to go with a standard XML
specification RSS .91