Prevent feed from updating a post when changes are minimal?

Many people who uses feedreaders or hosts a blog should be familiar with this problem: The author corrects a spelling error or a broken link, and “pop”, the feed reader registers the update and alerts readers of a “new item”. The readers click on the item, but wait a second, “didn’t I read this yesterday, is there something wrogng with my reader?” I spoke with someone who just started reading feeds yesterday, and she was asking “why does all my feeds update, I can’t see anything new in there, did I do something wrong?” This kind of system behaviour does not make it easier to win people over to the world of syndication.

One solution would be never to publish anything absolutely fool-proof, but in my case that would mean never publishing any posts at all. So I want to be able to do minor functional and cosmetic changes without having to alert my whole readership.

Now, this should probably be a client-side issue, but as a feed publisher I have no control over this, and neither does (do I suspect) the readers. Feed readers such as the popular Bloglines doesn’t include a way for the readers to specify a threshold for what counts as an update (is a one-letter change an update? Or a new line, maybe?)

I have a feeling I ask for something that can’t be changed on the server-side (without corrupting the feeds) because of the spesifications and how they work, but does anyone else have any opinions on this problem?