Further to the problem described above I also noticed that when run from the backroom debugger, the pipe returns data older then one would expect. I am certain that all of the feeds work and publish almost daily because I took them directly out of the ones I view most days using Thunderbird on my desktop, and they all have posts from the last few days as far as I can tell. But the data in the feed is from 5 or 6 days ago. And it is only retrieving a few new articles from several blogs which publish significantly more often than that. I can tell by comparing them to what I'm getting through Thunderbird. In the backroom debugger, none of the feeds are being fetched.
My software was checking it regularly, but so far there has not been a reported error. I'm not sure if I'm missing it, but mys software was checking it every 45 minutes. This is well below the limits described in the documentation (http://pipes.yahoo.com/pipes/docs?doc=troubleshooting#q11)