.1 includes an interesting new app called Reading List that is designed to run side-by-side with Internet Explorer and others apps that contains articles and other reading material you wish to save for later. Using this app, you can create a virtual reading list and return to your saved articles at a later time. It's just missing one key feature that would put it over the top.
Reading List uses the Share charm to do its work. When you find a web article or other document in a compatible app, you can share that article with reading list so that you can read it later.
To be clear, Reading List doesn't only work with Internet Explorer: You can use it with any app that correctly responds to its Share charm requests. In the shipping version of Windows 8.1, the Bing News and Sports apps can also share articles with Reading List, so I suspect the other Bing content apps—Health & Fitness and Food & Drink—will pick up this usage over time too.
To read your saved articles, launch the Reading List app. By default, it appears full-screen and provides a list of the articles you've saved.
When you select an article to read, it opens in the source app in Snap view, so you can continue accessing the other articles you saved for later.
Reading List offers the expected article management tools: You can search for articles if you've saved a lot of them, remove articles, multi-select articles for batch removal, and so on. (It also stores deleted articles in a Recycle Bin-like feature for a set amount of time which you can configure.)
Finally, Reading List also syncs across your devices: So you can save an article on your desktop PC and finish reading it on your tablet. One might imagine that a Windows Phone version of this useful app is on the way as well. It makes sense.
What Reading List is missing, alas, is a feature many would find most useful: It doesn't work fully while offline. That is, Reading List stores links to the articles you saved, but it doesn't cache those articles for offline use. So while some articles may be otherwise cached and still work while you're offline, others won't. And there's no way (currently) to fix that.
Hopefully, Microsoft will add some kind of offline functionality at a later time, though it's not clear how such a thing would work across the various compatible apps. (Some apps, like Bing News, already support this independently of Reading List.) As it is, Reading List is still a useful addition to Windows 8.1, and a feature you should know about.