comments have a bunch of references to resources
Simple: - most RSS readers suck so bad you can't even retrieve years old articles. So if you follow blogs that don't post often, you simply can NOT get any of their older posts. Imagine a blog that has one seriously good article once a month. Typically you can't get more than a year's worth of posts, so that's like 12 articles. Why? - the best RSS app I had on iPad let me archive feeds for a LONG time. I used it as a kind of a library. Returned to articles many times (philosophy and such). Most RSS readers out there have ZERO functionality in terms of archiving content indefinitely. (meaning : they typically have some leeway in max articles stored, or how old to archive feeds.. but you know you simply can not realy on the app to save your favorite articels, at some point they will be deleted). - inability to highlight text. Again, if I read something I want to be able to at least highlight some text. Most RSS readers don't do this. Instead RSS readers do the same thing every other RSS reader does. Basically, it's like the developers of RSS apps think that the only purpose of retrieving articles is for fueling some kind of "feed" addiction. Like the only purpose of content on the web is to satisfy an urge to quick scan and move to the nex article. It's like the devs of RSS apps are so drugged out themselves in this day and age of short attention span, that they can't envision other uses for a feed reader than satisfying this urge for the daily/hourly doses of "novelty". Click click click. Swipe swipe swipe.