Yahoo! Pipes breaks new ground on several fronts. It's a graphical development environment that runs in a standard web browser. It advances the Unix pipes metaphor into the web services age. But it's definitely beta software, and it's a bit underdocumented. So to help smooth over some of the rougher edges, here's a list of interesting tidbits that may save you some hair pulling.
Not every browser supports the Yahoo! Pipes Editor. These are the currently supported browsers:
Internet Explorer 7
Firefox 1.5 and higher
Not every data field you see in the debugger ends up in the output RSS feed. For example, in the Debugger, a Yahoo! Local module shows a bunch of data fields such as Categories and Rating. But the final published RSS feed only provides title, description, link, geo:lat, and geo:lon. If you need the additional fields, you'll need to use the feed in JSON format (see below).
Complex Pipes can take several seconds to run. Remember that a Yahoo! Pipe runs on the Yahoo! server. At any time, your Pipe request is competing with any number of other requests. For best results, you should save the output of a Pipe to a file on your server periodically (perhaps once an hour). By loading from this cached file, you'll get better overall performance and won't overtax Yahoo!'s resources.
There are filters, like the Regex filter, wherein you need to refer to an RSS field within a text field. For example, you may want to append the publication date to the ...