Emil Leong, writing on Twitter’s weblog:

Last year we began testing a quality filter setting and we’re now rolling out a feature for everyone. When turned on, the filter can improve the quality of Tweets you see by using a variety of signals, such as account origin and behavior. Turning it on filters lower-quality content, like duplicate Tweets or content that appears to be automated, from your notifications and other parts of your Twitter experience.

I think this is a great change overall, but I still have concerns. My biggest fears are algorithmic false positives and employees of Twitter having the ability to flag accounts manually — potentially silencing users for dubious reasons. I have no indication that this will actually happen, but you can never be too sure about a feature like this.