Web: Apps that show you links shared by friends are a common, but Nuzzel stands apart for three reasons: it's easy, it's customisable and it has a handy "news from friends of friends" feature.
Hook up this webapp to your Twitter and Facebook and it will analyse your feeds to find links commonly recommended by your friends. It puts them together to show you links in order of how many friends shared that. Each story shows the tweets or Facebook posts where it was mentioned by a friend. Click the link and you'll be taken to read it.
The feature I found most useful was News from Friends of Friends. As the name suggests, the first one tracks links from your friends' timelines as well, so that you can see what links your friends are likely to visit. It's a neat way of expanding your reading scope beyond what you usually see, but still keeping it in context -- you aren't likely to have many social network friends whose circles are wildly different from yours. In my usage, I came across some articles that I wouldn't have seen otherwise, but were still of interest to me.
You can also customise Nuzzel to show you links based on time or friends, and further filter the time based on recency, date or periods. It only goes up to last week though -- you aren't going to find links for your entire social networking history.