RE: [RSS-DEV] Merge threads - who, what, why
- As others have noted, the container syntax in RDF was badly concieved,
even more poorly explained, and is not necessary for the effective
representation of syndication feeds. Representing sequences in logical
languages has always been a bit of a kludge, and RDF is no different in
this respect. It was a mistake for RSS1.0 to use this misfeature. Future
attempts at RSS-in-RDF should eschew the use of RDF containers. But we
should not throw the baby out with the bathwater and conclude that RDF
is innappropriate for syndication feeds because of this mistake. In
fact, I would make the opposite assertion: as RSS 1.0 has effectively
demonstrated, there is no reason for using any notation other than RDF
for this purpose, *assuming the appropriate use of RDF*. What does that
mean? It means don't use rdf:Seq.
Blank nodes exist in parsed RSS because of the use of rdf:Seq to
enumerate items. Eliminate the use of rdf:Seq and there will be no blank
nodes. Alternatively, ignore the blank nodes and the only thing you lose
is the ordering, which, as previous threads have noted, is not much of a
Further, there is nothing about RDF that works counter to the
requirement for impermanence. Simply parse the feed periodically and
throw away the previously created triples. If you want to maintain a
monotonically growing historical record of what was fed, what Phil is
doing with timestamping is in the right direction.
We carried out a similar experiment in February of this year using
Meerkat feeds; because the metadata in those feeds at that time was
somewhat impoverished, it's not very impressive, but a faceted metadata
search interface running on top of an RDF query engine using RSS feed
data can be viewed at
To make this point with fresher data, I've also put up an example search
interface generated off of the content in today's XMLHack feed at
http://w2.bpallen.com/spout/search.html?model=xmlhack. This took all of
2 minutes of form filling, works entirely off of an RDF technology
foundation, and is an example of how RDF technologies can be easily used
to build value-added RSS applications, *assuming the
RSS/syndication/aggregration community does not walk from the
achievement of RSS1.0.*
Bradley P. Allen
bpallen technologies LLC
5155 West Rosecrans Avenue, Suite 1078
Los Angeles, CA 90250 USA
phone +1 310 491-3424
fax +1 310 379-0231
From: Shelley Powers [mailto:shelleyp@...]
Sent: Monday, September 23, 2002 7:17 AM
Subject: [RSS-DEV] Merge threads - who, what, why
There seems to be three separate threads running along the lines
of "Who are we and what are we trying to accomplish", mixed in with
proofs and justification of keeping RDF in the mix. How can the
energy expended into these threads be coalesced into a determined
I asked the question, here and elsewhere, who is your audience? This
isn't marketing or make work. This is a genuine attempt to understand
what this group hopes to accomplish other than working with cool
technology for the sake of the technology. What is the business of
If RSS, past and current, is based on providing syndication and
aggregation feeds, and nothing more, than I agree with those that say
RDF adds nothing to the mix, and not because RDF adds complexity --
the reason is because the business of RSS isn't necessarily
compatible with the business of RDF.
In the last few weeks, Phil Ringnalda has been working on a
application to process RSS 1.0 files and combine this with FOAF to
provide a sophisticated interface allowing us to find who has posted
or commented on what topic. Yesterday he hit what is probably the
core difference between the business of RSS and the business of RDF --
the fact that tools generate labels for blank nodes, and that these
labels will vary each time the same file is parsed. (See
http://philringnalda.com/archives/002327.php). RDF/RSS (RSS 1.0) has
RDF is a meta-language for describing items that exist in
such a way that this data can be processed with the same set of tools
and combined with a great deal of confidence that this mergence
results in a valid pool of rich data. It is literally a markup
version of the relational data model, and as such, is extremely
useful and necessary to help with the chaos that XML created.
However, there is an implied persistence to the items described with
RDF, the same as there is with relational databases. Data may change
and be removed, but there is no temporal self-destruct attached to
RSS, as the majority of those who view it (the users, not the tool
developers) is a syndication feed -- nothing more than recently
updated items that can be polled and aggregated. There is no implied
persistence. In fact, the business of RSS is based on impermanence.
This is a major difference in 'business' between the two concepts.
>From a database perspective, you rarely use an RDBMS when a flat fileof comma-delimited data is all you need.
If this group wants to continue providing a specification that
defines syndication feeds, then it needs to consider that RDF not
only doesn't buy the group anything -- it can harm the tool
developers that use the spec. (Not to mention that trying to use RDF
inappropriately can actually negatively impact the acceptance of the
If, however, this group sees that what they're working on transcends
throwaway syndication feeds, then it needs to formally define exactly
what the business is _before_ trying to create a spec that implements
it. Hence my questions: who is your audience and what are you trying
Specific instances of technology isn't an answer to these questions.
This isn't answered by, "Well, we'll just continue as is and use XSLT
to handle any problems in the future". If you find yourself answering
these questions by referencing technology, then either you're missing
the point, and or (more likely) I'm doing a piss-poor job of
What is the problem this group is trying to resolve? What is the
benefit this group is trying to provide that no other technology or
specification provides? Who is your audience? Not the tool
developers -- people don't write tools for no reason. Who are the he
consumers of the tools developed.
What are you trying to accomplish?
This understanding of the basic business goes beyond a name, though
the name of 'RSS' is drastically adding to the problem by forcing a
type of business on this group that this group really doesn't want,
as well as adding an element of competition that is both unnecessary
Perhaps this group really isn't interesting in throwaway syndication
feeds. Perhaps this group is interested in finding ways of describing
publication units that may or may not be smaller or bigger than an
individual web page. And a side benefit of this is that the data can
be used for aggregation purposes. Or not. I don't know -- the group
hasn't told me what the business is.
If you continually have to justify the use of something over and over
again, either you're wrong, or your audience is wrong. In either
case, you need to re-focus your efforts, and either find a different
audience, or stop beating a dead effort.
I guess this was more than my 0.02 worth, wasn't it?
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- Unfortunately illness kept me away from my machine for a few days, and is
currently reducing my desire to correspond quite drastically. It is also
likely to make my normally rambling style even worse.
However Shelley's main question about the "business" of RSS is important and
I'd like to have my 2c.
It seems to me that there are three ways to define the purpose of a
technology. One I will label "designed", one "adaptive", and the other
The designed way is to have a purpose decided by necessity or inspiration
from which you design the technology. The technology then apparently springs
from the forehead of the individual or group who create it fully-formed,
since it is generally only after much work that the public is made aware of
The adaptive way is to define a purpose by examining the uses to which it's
predecessors are used.
The reductive is similar to the adaptive, but more forcibly redefines the
purpose by producing a technology that can no longer be used for some of the
tasks it's predecessors were put to.
The parthenogenesis of the designed way tends to produce "purer"
technologies with limited application, the adaptive way tends to produce
messy technologies with a wide range of applications, many of which it does
not match very well. As annoying as the inelegance may often be the latter
type tend to be the most useful. The reductive method tends to result in
something between those two.
Many technologies start with a designed version 1.0 (or 0.x when the
author(s) choose to acknowledge that they don't consider it finished) and
are then used for purposes outside of their initial use-case which feed into
an adaptive definition of the purposes of later versions. To elide
historical detail for the sake of brevity the Internet's designed goal is to
be a military and academic communication network that can survive total
destruction of many of it's nodes and the Web's designed goal is to provide
a simple way to write up scientific papers which would include references to
other such papers, hypertext being used to make those references more
useful. The Internet and the Web both have current uses quite different to
those, and many of their parts are used in manners further removed from
their origins (e.g. the use of HTML in many Windows technologies doesn't
even make use of the Web's distributed nature).
I maintain that RSS is such a technology. It's designed purpose is the
syndication of "news" items from individual websites to a portal website, to
be more specific to the MyNetscape portal website. It was *not* designed to
be of any particular use to bloggers, aggregators, or metadata providers,
but it *does* serve them and others.
Which makes answering Shelley's question a bit tricky. Casting the net wide
there are real-world use cases now which include some cases quite close to
the original intent, but also some that are quite disparate (e.g. using
RSS - either in accordance with the spec, or else as a mere provider of
vocabulary - to provide a table-of-contents to a collection of RDF documents
describing a site or other system). As such the best answer I can think of
for the purpose of RSS is:
"To provide information about web resources that change often enough to make
such information worth giving".
Which is a thoroughly unsatisfactory answer really, but not a useless one,
for it still has implications in our decisions if we intend RSS+ to remain
useful to all or most of its current users.
In particular it means that dropping features, including features that are
by-products of design rather than deliberately built into the format, should
only be done with extreme caution. With such a wide range of use-cases any
feature could prove vital to someone. This includes RDF, inherent (as
opposed to spec-defined) ordering, the ability to work as a "pure" XML
format, and in fact everything that someone (including myself) has suggested
The reductive method could be applied here. We could define the use-case of
RSS as, for example, "syndication of blog items", which is pretty much the
use case of RSS0.92+/RSS2.0 and design appropriately, dropping features such
a case doesn't need.
Dropping such a feature is likely to lead to a split as developers no longer
served look elsewhere, indeed that is part of the reason for the
RDFSS/RichSS split. Such a split may indeed be a good thing, but there are
obviously disadvantages in the loss of momentum and critical mass that it
In all I would avoid a reductive definition of RSS+'s purpose. If needed
such reduction can be provided by APIs in only providing access to some of a
feed's information without necessitating the same reduction in the format
This isn't conducive to simplicity, but it doesn't preclude it either, and
everyone benefits from simplicity (that said I'd be prepared to sacrifice
simplicity from an RDF perspective to gain simplicity from an XML
perspective - as in using Collection).