One of sTeams features is link objects. That is objects that point to other objects. (ˢᵒᶜⁱᵉᵗʸlog) uses link objects to build topical logs. Each topic links to articles related to that topic.
sTeam link objects are not transparent. When you access a link object it needs to be handled specifically to extract the object (in our case the article) it points to.
Handling link objects separately has the advantage however that the target article can be adapted to the location of the link object.
One case where this matters is if an article contains relative urls. If the article /a/hello includes an image src="logo.png", then the browser will load the image from /a/logo.png. Now if /b/world is a link object for /a/hello it would try to include the image from /b/logo.png. Obviously, that won't work, so when presenting the article though the link object we need to parse it and replace relative urls so that they all point to items in relation to the location of /a/hello
The rss feed has also been improved to handle link objects, but in difference to above, here the link object is simply transparently replaced with the original object. Because the feed is accessed in a different context from the whole site, the link location is less relevant. Also if an article is linked from multiple feeds, all feeds will show the same object, thus allowing the feedreader to notice duplicates.