While there are a number of different ways you can try to generate a revenue stream from your RSS feed, from the people who have subscribed to your RSS channel rather than read your blog directly, my personal experience is that it's barely worth the effort unless you have an extraordinary level of readership.

For example, one of the more common solutions is Feedburner, which offers the ability to insert advertising banners into your feed in a manner very similar to how Google AdSense lets you slip ads into your blog itself (and, yes, you can also use AdSense to include ads in your RSS feed too, they do have AdSense for RSS, as I wrote about here: Best practices with Google AdSense for Feeds).

The problem is that there's already a bit of a dilemma with RSS and I believe that advertising just exacerbates the issue, which is whether to have "full feeds", where you make the entire blog entry available to feed readers, or "partial feeds", where they get a snippet, a tease, hopefully enough to bring them to your blog to read the full article and be exposed to your advertisers. A partial feed + advertising is something that I've heard again and again is just too much, too greedy, and it turns off a lot of potential subscribers.

On the other hand, when I look through my own 150+ feeds that I read, there are plenty that do just that, including the Wall Street Journal and BusinessWeek, so perhaps it's not as egregious as I think?

I suggest that you do what all good Internet marketers do: you test it.

Sign up for Feedburner or a similar service and then add the adverts to your RSS feed for a month. See what kind of revenue - if any! - you gain and pay attention to your daily subscriber count to see if there's any sort of backlash or slowdown in new subscribers. Then turn it off for a month and again watch your stats. Do you get more subscribers when you don't include advertising? Do you find that you have more churn, more people leaving your list when the ads show up? If you made any money, is the cost of losing subscribers worth the benefit of that income?

I hope that helps you figure this out. Perhaps some other bloggers can also chime in here and let us know their own experiences with advertising in RSS feeds, whether it proved lucrative and whether they received any negative feedback from subscribers?