When you set up your blog RSS feed you’ll have to decide whether you want that feed to publish as a full text feed or a summary. The full text will publish your entire blog post within the RSS feed while the summary will post just a couple of paragraphs and link back to your blog post. There are advantages and disadvantages to both methods. RSS feeds that offer summaries tend to receive more click throughs back to the website, but that’s really the only major benefit – and it may not be a benefit at all if a high click through rate means a lower overall readership.
Here is a video that I found (an older one but still very good!) about RSS Feeds:
Anyway, continuing the tips regarding full text feeds will likely lead to more subscribers. This increases your overall readership and gives you wider distribution of your blog content. Plus, you are more likely to get links from your readers. Also, full text RSS feeds get republished in full, which means any links within those blog posts have greater potential to pass link juice back to you as part of your off site search engine optimziation efforts (aka. link building) Some blog lists and feed directories are picky about partial lists and may leave you out if you deliver your RSS feeds in summary.
Finally, potential re-publishers like full text feeds because it allows them to keep visitors on their site. That means more potential inbound links for you. Should you publish your feeds as full text or summary? It depends. Do you want to increase your SEO advantages? If so then publish the full text. If you value more click throughs back to your blog from those feeds then publish your feeds in summary.