Hi Doug and Norm,
I think that any solution that requires that you download something that you don't want to download so that you can delete won't work, for one thing, because you can't control the number of programs are in the other persons collection.
For Doug, this kind of ties in to what I was saying about the problem of managing these feed. If I'm following your collection, and you suddenly add 30 programs to it and the limit on items displayed in the RSS feed is 30 I could push out all of your own collection without even knowing it. I wasn't thinking through various scenarios last week and getting a headache.
Do you have a model of how you're thinking the system will function? It might help. All of this is going to get confusing pretty fast.