リツイートのふぁぼ・RTをWeb公式で非表示にするChromeユーザースクリプト。インストール方法は（ http://egyo.hateblo.jp/entry/20101022/1287713022 )。

retweet_action_mute.user.js

// ==UserScript==
// @match https://twitter.com/i/connec*
// @author onteria_
// @version 2.0
// ==/UserScript==

// Author: @onteria_
// This is a script that is meant to hide recently
// added "retweet of retweet" and "favorite of retweet"
// which have no options to disable and can get rather
// noisy

// Variables
// Tweets container div id
var timeline_id = "timeline"
// * of Retweet class
var retweet_action_classes = [
"js-activity-favorited_retweet",
"js-activity-retweeted_retweet"]

var new_tweet_bar_class = "js-new-tweets-bar"

function hide_node_if_class_match(node, class_list) {
	for (var i = 0; i < class_list.length; i++) {
		var check_class = class_list[i]
		var node_classes = node.className.split(' ')
		
		if ( node_classes.indexOf(check_class) != -1 ) {
			node.style.display = 'none'
			break
		}
	}
}

function check_new_tweets_bar(node, bar_class_name) {
	var node_classes = node.className.split(' ')
	
	if( node_classes.indexOf(bar_class_name) != -1 ) {
		node.click()
	}
}

var stream_container = document.getElementById(timeline_id);
var stream_items = stream_container.getElementsByTagName('li')

for (var i = 0; i < stream_items.length; i++) {
    hide_node_if_class_match(stream_items[i], retweet_action_classes)
}

// This part checks for infinite scroll changes
// or tweets added by clicking on the new tweet bar
// it uses MutationObserver to handle these changes
// https://developer.mozilla.org/en-US/docs/Web/API/MutationObserver
var observer = new MutationObserver(function(mutations) {
  mutations.forEach(function(mutation) {
    for ( var i = 0; i < mutation.addedNodes.length; i++) {
		hide_node_if_class_match(mutation.addedNodes[i], retweet_action_classes)
		check_new_tweets_bar(mutation.addedNodes[i], new_tweet_bar_class)
	}
  });    
});
 
// Only listen for stream mutations to save resources
observer.observe(stream_container, { childList: true });

Chrome user script that hides retweet favorites and RTs

Chrome only, not Mozilla Firefox?