It appears to me full content RSS feeds are actually helping and compounding the splog (spam blog) problem. Splogs or spam blogs are blogs which are created by using syndicated content of other blogs, automatically aggregated, to increase their PR and AdSense dollars. Splogs don't add value to the system, rather devalue the whole blogging concept. Splogs also make concepts like PubSub irrelevant.

Proponents like Dave Winer and Scoble prefers full content in RSS feeds.

The upside is that viewers do not have to click again to go to the website to view the full content. They can view it directly in their RSS reader only. The downsides for the site author is that he doesn't have control over the layout of his content and also presents him with a challenge to monetize his offerings which he can do when the viewer comes to his page. Feed advertising is an option. However the success rate is not worth writing home about as far as I know.

The biggest downside IMHO is that such feeds makes it very easy to re-purpose them to create splogs which ultimately devalue the whole blogosphere.

A RSS provider (any blogger for example) has no active control over the usage. He can at most add copyright messages to the feed thereby alerting common public that his feed is being misused.

What are the solutions?
I suggested today headline only RSS feeds which can satisfy both camps.

If you still prefer full content feeds you can use a facility such as provided by my feed copyrighter plugin for WordPress to automatically add copyright notice and illegal usage notification to the end of content along with option to inform the original author. I plan to release a new version soon to make it harder for perpetrators to automatically delete such messages from the feed by simple filtering techniques. So far however no such attempts have been reported despite widespread usage.