The presentation about the Semantic Web Pipes from DERI in the WWW 2008 conference, developers track was very impressive. It is based on the idea of yahoo pipes of mixing and channeling data through operators, but for semantically structured data which offers more powerful operations. It also offers impressive GUI for handling the pipes though not as beautiful as yahoo pipes GUI. Sometime ago I had also presented similar idea of Semantic Web pipes for SocioBiblog, a semantic blogging system for decentralized flow of bibliographic information in communities. However, it only had limited operations of mixing feeds and filtering by metadata elements.
Semantic Web Pipes