The fad for social networks and crowd-sourced based organization of data still reigns, and, my friends, this is sad. The so-called wisdom of crowds only exists because, if you invite a crowd to work on something, you have a statistically higher chance of having one really smart person within the crowd than you would if you just invited one person. Nobody suggests there is any wisdom in commitees; even smart people get pushed to conform.
The social thing is actually an answer to a different question; attention.
We can only pay attention to so many things in a given day, so having access to what other people pay attention helps us improve what we pay attention to, assuming we have any metric for quality. There are a few metrics for quality, like grammar, vocabulary choices- as well as a few ways of grouping like with like- many tend to link to the same story or quote the same quotes.
But what do I constantly see? X number of people liked this, or your friends liked that. Perhaps the worst are the thumbs up/thumbs down rating systems on individual posts. If I am already reading it, what does any of that matter? I need info that helps me see whether or not I am getting quality; I am already the king of quantity, with 697 feed subscriptions and a propensity to add more at the drop of a hat. I don't need to pass judgement on one item in isolation to the rest; I need to be able to rate items in relation to one another. Only then does it become clear whether or not I'd be better of paying attention feed A, or dropping it in favor of new feed B.
I do occasionally try to figure out a way to do this myself. How much Xquery do I need to learn in order to figure out if I could use an XML database in conjunction with a feed reader, rate the items against one another using various simple filters, and then push the items out again in order of quality in another feed?