There's a good chance that you read this blog from its RSS feed, that's how I follow most publishers without a regular schedule or sites that publish no more than a couple of pieces daily. For the rest, there's Twitter. Some feeds I subscribe to truncate their articles and exhibit a single paragraph, a couple hundred characters or just a Twitter-like description, a link by the end of the excerpt takes you to the article in the original site and I'm declaring war to them.
A publisher with shortened RSS feeds may be unaware of it or incapable to either fix it or hire someone to do it. However, the plausible motive seems to be advertisement since RSS feeds are naturally exempt of them. How advertisement undermines the web boosted a debate on app supremacy and web's downfall recently and, although I comprehend that these publishers rely on page views for revenue, as an user I'm disappointed when they whack at my experience to achieve them, particularly in a format where users likely have an ad blocker.
Before mentioning the little gem expanding RSS feeds for me, inquire the sites on the shortage of full-text feeds, perhaps enough interest sparks a healthier approach by the publisher. As always, use this in moderation.
After searching for a service to expand a RSS feed and deliver the full-text version, I found a free service on beta called Feedex. Just paste the feed's url and the service will deliver its own alternative RSS to subscribe to the service. Feedex has been on beta since 2011 and I can't vouch for its longevity, but it works; some feeds don't supply a shipshape result, but most do and you won't be opening in-app browsers anymore, as it seems to be the direction everything is going.