Twitter officially announced “Mute” button for its iPhone, Android and Web users. With this Mute button, you can selectively turn off the posts of particular users. So you can mute users you’d like to hear from less. If you have enabled Muting for a particular user then the tweets and retweets of the muted person will be no longer visible in your timeline and also you will not receive push or SMS notifications from that user. The advantage is that the muted user will not know that you have muted him/her.
If you want to unmute any user, you can do it anytime. To mute any person, just navigate to settings or more option in your Android, iPhone or twitter.com and tap on “Mute @username”.
Screenshot from Web: