This example splits a Yahoo! Health News feed in two, using the Split module. Each feed is then sent through a Filter module. The first Filter looks for stories on weight, while the second Filter looks for stories on drugs. After filtering, each feed is then sent through its own Regex module, which we use to annotate each item title with its corresponding category. So a story titled "Overweight kids face widespread stigma (AP)" becomes "[Weight] Overweight kids face widespread stigma (AP)".
Finally, we merge the two feeds together using a Union module, giving us a single, categorized, news feed.
Pipe Web Address: http://pipes.yahoo.com/pipes_team/QMrlL_FS3BGlpwryODY80A