That's a good question and I'm really not sure. I know a few years ago Google was seeing my feed as duplicate content and most of my search traffic disappeared for a time until I fixed the issue. I don't think the same problem exists now.
On the other hand I always assume if Google can collect data about something they'll try to use it in some way if they think it will help improve search results.
I suppose you can test this by searching from some things that are only in the feed. Add something unique that doesn't currently have search results as a start.
Hey Steve. I have an interesting thought about edgray's post regarding how to use hidden content. Before I post it I wanted to run it past you. How much weight does Google put on RSS feeds?
Example: Let's say I have a page of videos - not ext but my RSS feed for that page elaborates on each video with text descriptions and a link back to the video page itself. I know a guy here in Costa Rica that was recommending that to me a while back but I was worried about the difference between "actual" and "feed" (we know Google is arrogant but not stupid).
I wanted to throw this into your one ear to see what you think before posting anything publicly.