It is no longer possible to see @reply conversation directed at people not already in your follow network. There are several issues that arise from this change, but the great sin of Twitter may be a UX problem.
Why Design?
Philippe Starck gave a powerpoint-less lecture at TED last March. The topic was “Why Design?” According to Starck, we contribute to the big idea—the continued evolution of our existence—by working within our current contexts and doing the best we can to shape our world.
The Evolution of the Biggest Wiki
Think of wiki, and most people automatically add -pedia. The popular understanding of Wikipedia is of this somewhat controversial source of information that is both deep and unreliable, where a few people do the work and everyone else benefits. Of interest recently is how age and acceptance is changing both the perception and activity around Wikipedia.