Introduction

In a content syndication setting content is transferred from the syndicator to its subscribers. Usually these individuals, portals, or other syndicators have subscribed to a channel which defined a particular update pattern and a predefined message format.

In many cases not directly content is exchanged, rather than links to the content. The popular RSS syndication defines the concept of a channel which can contain a number of news items together with an optional image logo. An RSS document is then either pushed to the subscriber, or - more commonly - pulled from the syndicator.

The simplicity of RSS is both a bane and a blessing: The news items consist of URLs together with a headline and are packaged in a channel definition serialized in XML. While different flavours of XML-RSS exist (Version 1, 0.91) software support and a rich offering makes it attractive to act as either content producer or consumer.

The inherent price of this simplicity is that RSS is conceptually restricted to basically syndicate headlines. There are ways to use RSS modules to extend the amount of meta-data to be used within a channel object. For more drastic extensions in the type of content the syndicating parties will have to use either RDF or Topic Map technologies.

In the following we want to report about our experiments to use TMSS, Topic Map Site Summary, as a simple Topic Map interpretation of the conventional RSS channel. We will outline how such a channel can be defined by using a TMCL (Topic Map Constraint Language) and how channels can be extended into a general Topic Map syndication scenario. The Perl modules which we have prototyped in these experiments may demonstrate how this can be useful in practical web development.