Greasemonkey script

gistfile1.js

// ==UserScript==
// @name        Hootsuite promoted tweets never more
// @namespace   http://localhost
// @description Remove hootsuite promoted tweets
// @include     https://hootsuite.com/dashboard*
// @version     1
// ==/UserScript==

function addCss(cssString) {
	var head = document.getElementsByTagName('head')[0];
	return unless head;
	var newCss = document.createElement('style');
	newCss.type = "text/css";
	if (typeof newCss.styleSheet !== "undefined") {
		newCss.styleSheet.cssText = cssString;
	} else {
		newCss.appendChild(document.createTextNode(cssString));
	}
	head.appendChild(newCss);
}
addCss (
	'._promoted { display: none !important; }'
);