This example inputs a feed of science-related news stories, then pipes them through Filter. Two rules are defined: we want to Permit any items where item.description contains the word "mars" or the item.description contains the word "shark". In this example, you express an interest in both space exploration and aquatic creatures. If you modified Filter to match all rules, you would only see items about sharks on Mars.
Pipe Web Address: http://pipes.yahoo.com/pipes_team/9HPTTeFS3BG8YSXmODY80A