While Twitter generally presents lots of stuff that flows by far too fast to make any sense, there are ways to place filters or look for specific elements. For example, I have a persistent search pane in PeopleBrowsr for the #kmers hashtag that is being used by many people who are interested in knowledge management. So, I can scan the notes and links people post with that hashtag. It's a way to get slightly more focused content from Twitter than the wide array of stuff that comes through without filters.
As it happens, John Reaves pointed to a piece he wrote on just this topic of information overload and the means we have for dealing with it all. Here is an interesting metaphor from the middle of his Scanning the Content Jungle. This should sound very familiar to people who have been paying attention to aggregators and blogging. And to newspapers before that.
Here's an hypothesis and a metaphor. What we do as humans, and descendants of Ardipithecus who stalked the physical jungle, is to scan a complex environment continuously and with all our senses. Arguably what we are scanning today is no more complex than what our remote ancestors had to deal with: a dense living ecosystem full of danger and opportunity. 360 degrees of sound, sight, smell, touch, kinetics. All of it is data and always has been. What digital networks and community interfaces have done is not so much increase the amount of data that we have to scan, as to abstract and thereby extend our senses around the world and around the clock.
When I see this kind of article, I think back to a science fiction series from 20+ years ago, where the story describes a society that is "managed" by a computer that has been monitoring and guiding human evolution for generations upon generations. (The people don't know that this computer exists - until one of the characters figures it out.) At one point there is a scene where the computer acknowledges that it discovered that it could never remember absolutely everything, so it developed algorithms to describe common patterns and predict outcomes from them. And it used these patterns in observing and influencing the world.
In other words, it had some really cool filters that helped it focus on the information that would be relevant. This is one of the things I want my personal knowledge management to help me do. One of the filters is the tools I use to sort and organize the stuff I have. Another filter is the people and things I read in the course of that first level.
I found the entertaining Demotivators-style photo above from catspyjamasnz, quoting a Clay Shirky talk from at Web 2.0 Expo NY in 2008 - someone who has been thinking on this topic for a while.