Dave Munger in The end of the RSS experiment presents the results of data collected to analyze what happened when his web site Cognitive Daily turned off partial RSS feeds and substituted full RSS feeds. A reduction in site page hits corresponded to the publishing of the full RSS feeds, presumably because feed reader users had no need to return to the web site -- where ads are visible.
Munger suggests that one option to continuing with full RSS feeds would be to embed ads within the feeds themselves; that way visitors to the site and feed readers would see the ads.
Comments to Munger's post include those who feel that an advantage of full feeds is specifically that ads are deleted by most feed readers, so embedding ads would be counterproductive.
Another commenter points out that an inherent advantage of returning to the original post, even when full feeds are available, is the ease with which comments can be tracked.
I am a believer in full feeds for what I publish here on All Kind Food. But I don't publish ads. I'm aware that my publishing full feeds (such as this one, for my "Managing Technology" section) means that readers of the feed can substitute the full feed for a visit to All Kind Food.
Based on a regular review of my own web site statistics, I've concluded that this probably results in a net increase in eventual visits to my web site, simply because more people are potentially reading my posts when they scan through their feed readers and feed aggregators.
Besides, my goal is to get my stuff read, not to sell advertising. My site is basically one big ad for me and my consulting services, so the more people who visit wherever my stuff shows up -- assuming the outlet preserves the basics of my original post and its content, which I know is not always the case -- I'm happy, even if I don't really have a good handle on the total number of readers.
I am a believer that the more one is published, the more likely it is that someone will read one's publications, either because the publication was referred from another site, it was subscribed to already, or it was located via a search engine search. A full RSS feed amplifies the number of potential exposures to potential readers, so I'm happy with that.
Would I feel the same if I did publish advertising, knowing full well that people could substitute an ad-free full feed for a visit to my site? I can't really say. Intuitively I believe that more feed readers will eventually net out a larger total readership for my original posts, especially among those who are potential returning readers. But I don't have any data on that.
I do know that I get a significant number of referral hits to my blog when one of my posts is picked up on the front page by Social Media Today, an aggregator I belong to. Since Social Media Today posts the entire feed, why would anyone come to my site from there if they can already get the full post there? The answer to that question, I guess, is that readers might be interested in seeing what else I have published and coming to my site is an easy way to follow up that interest.
Also, I'm not opposed to ads, even though I would prefer they not show up in the feeds I subscribe to and read regularly. Intrusive or ugly ads definitely do keep me from returning to a site; for example, I rarely anymore visit a Sys-Con Journal where I once published some articles on "web 2.0 adoption" since the advertising experience is such a turn-off. Also, I can tolerate Facebook ads but not MySpace ads.
So I guess I would suggest to the folks who are reluctant to publish full feeds for fear they will reduce ad revenue is -- if you need to publish ads, fine, but at least try to improve the ad experience on your site so that ad content is an inducement to visit your site, not a detractor.