Providing conduits through the internet backbone, they combine and filter data feeds to create for you a stream of useful information. They're Yahoo! Pipes and now <alt> Mashup technologies can channel HTML content through them.
Link to HTML Version: http://altmobile.com/web_docs/Mashup%20Designer%20for%20Yahoo%20Pipes.html
Link to PDF Version: http://altmobile.com/pdf/Mashup%20Designer%20for%20Yahoo%20Pipes.pdf
