RSS (Really Simple Syndication) is a format used for the publication and syndication of web content. While several frameworks,
techniques and algorithms have been proposed and studied for the processing of complex queries on data streams, current RSS
reader and aggregator software and services do not propose advanced query facilities.
We designed and implemented a prototype RSS aggregator service, called Danaïdes, for the processing of complex queries on continuously updated RSS feeds and of progressively producing results.
We demonstrate the prototype and its several user-interfaces with a geographical application using geoRSS feeds. This work
is a practical application of our research on progressive query processing algorithms for data streams.