We're always talking about podcast subscribers and the feed, but let's not forget that there has yet to be a credible study that shows over 50% of any given podcast's listeners even use a podcatcher. Many listeners either go to the show site and direct download, or they use a normal news aggregator and just click through from there. It's the people using the normal aggregators that I'm concerned with in this post.
I ran across these two posts, both by TDavid on Make You Go Hmmm. Post one shows a feed who's owner has gone hog wild with Feedburner's "Feed Flares". The flares are about 3 times longer than the actual post. This is definitely distracting and obviously taking away from the content of the post.
Post two shows a single item in a feed with no less than 10 advertisements in it. TEN!
Moral of the story? Keep it neat. Putting bells and whistles in your feed just because you can, or littering the thing with ads is surely going to drive your listeners/readers away.