Firefox trick: more speed and less tracking with Decentraleyes addon.

Firefox trick: more speed and less tracking with Decentraleyes addon. Many websites uses libraries and diverse ressources that are delivered to your browser trough centralized content delivery networks (CDN). This takes time and allows tracking (as you need files from the same CDN for many different websites and, yes, they can track you even if you don't allow cookies from them). Decentraleyes catch these request and replace them with a local request, bypassing CDN, download time and tracking.

Supported Networks: Google Hosted Libraries, Microsoft Ajax CDN, CDNJS (Cloudflare), jQuery CDN (MaxCDN), jsDelivr (MaxCDN), Yandex CDN, Baidu CDN, Sina Public Resources and UpYun Libraries.

Bundled Resources: AngularJS, Backbone.js, Dojo, Ember.js, Ext Core, jQuery, Modernizr, MooTools, Prototype, Scriptaculous, SWFObject, Underscore.js and Web Font Loader.

Note: Decentraleyes is no silver bullet, but it does prevent a lot of websites from making you send these kinds of requests. Ultimately, you can make Decentraleyes block requests for any missing CDN resources, too.
https://addons.mozilla.org/en-US/firefox/addon/decentraleyes/