Some RSS and Atom feeds contain condensed versions of the articles right in the XML file. These can range all the way from an empty page with just a link to the real article on-line, up to a full copy of the article complete with photographs and other images. Many feeds are somewhere in between, a one or two sentence summary with no links or images, or maybe a single image and a paragraph or two summarizing the full article.
The biggest benefit of embedded articles is speed. Since they were already downloaded along with the article headlines you don't have to wait for another download when you tap a headline to read it. Another plus is that they are often less cluttered and more readable than the full on-line version of the article. The problem is that support for embedded articles is sporadic. Many popular feeds have no embedded articles at all, and of those that do a great many only contain a short summary or just a link to the online version. For once, RSS seems to lead over Atom in this area. In theory Atom should be a better source of embedded articles since a place for them is explicitly defined in the standard. RSS feeds have a "description" node in each item that sometimes contains the article body, but often is only a summary or just a link, or even missing entirely. Atom, on the other hand, has one mandatory location called "summary", which usually contains what the name implies, and another optional, but recommended entry called "content" which is supposed to contain precisely what we are looking for. Unfortunately, the "optional" mandate is taken very literally in the Atom world, and the "content" is very rarely found. RSS is much more likely to have usable content in "description" than Atom is to have "content".
For Atom feeds, if "content" is included in the XML it will be used as the embedded article, otherwise "summary" will be.
The default setting in multiFEED is to display articles by downloading the body and displaying with QuickView, but you can change the default or specific feeds to display the embedded article instead. Unfortunately choosing which feeds to use this with requires trial and error. Set a feed to use "Embedded" and see what you get. If you don't like the result, change it back. If you find that a feed's embedded articles are usually good enough, but you sometimes want to see the full article, then view it first in the embedded viewer and then tap QuickView or Browser on the action bar to launch the associated browser when you need to see more.
Two popular feeds that contain useful embedded articles are: