It's not exactly a silent spring, but a recent change made to Twitter's settings has already greatly reduced the tweets its users are witness to. In what the company called a small settings update, users no longer see public replies sent by friends to people they themselves are not following. (Fragmented conversations, they are called.) This isn't a small change at all, it's big and it's bad. The new setting eliminates serendipitous social discovery.
The new policy isn't something you have to opt-in to. It's not something you can opt-out of. It's true for people who use 3rd party Twitter clients to read their Tweets. It's more fundamentally closed than Facebook is; on that site people may not be able to view the profiles of strangers talking to my friends, but I can see that the conversations are happening and I can read the comments. This new Twitter policy breaks one of the fundamental rules of social activity streams: that people can discover new people by seeing who is conversing with the people I already know.
Twitter Puts a Muzzle on Your Friends: Goodbye People I Never Knew