I am really disappointed that advertising is finding its way into RSS, although Im kind of surprised that its taken this long.
I have just removed InfoWorld's feeds from my NewsGator subscription lists. I kept getting the same stories with a different advertisement at the bottom. For example, between Saturday at 2:00 PM and Sunday at 9:00 PM, I received 12 posts entitled "Update: Teenager arreested in Blaster case". These 12 posts were identical except for the advertisement at the bottom. The funny thing is that the first post didnt contain any advertisement.
If you want to bombard me with advertisements via RSS, it would be nice, if you would limit it to one per post. When the post goes out, stick the advertisement on it and call it good. No need in sending me multiple posts. This is almost as intrusive as those annoying popup windows that came about in the web browser (which I have managed to eliminate with the new Google toolbar). This intrusion may be a little more, because really what the posts are doing are wasting my time. I sign up to feeds to get the information I want when I want it. I dont necessarily want to waste my time clicking through identical posts.
I dont have any way of blocking duplicate posts from my subscriptions, so my only course of action is to unsubscribe from them.