Msg#: 3329555 posted 8:24 am on May 7, 2007 (gmt 0)
I think it will depend on the feed reader application they are using. It's possible that some may see the changed links as new and mark them unread. However, I think that for most the <pubDate> will sufficient to indicate the date of the <item>.
I've never tested this. You may want to try a few of your visitors' top feed readers and test them out with sample feeds. I'd be interested to hear your results.