With its Social API, Firefox became the only major Web browser to offer a way for social network content and notifications to live inside your browser alongside Web pages you’re viewing. The API launched in Firefox 17 last November with just one add-on using the API, though a pretty significant one—Facebook. Today’s release of Firefox 20 adds more social networks to the mix: Cliqz, Mixi and msnNow.

The API makes turning these social integrations on and off incredibly easy. For example, if you browse to Facebook’s Messenger for Firefox (Opens in a new window)page, all you have to do is press the “Turn On” button.

The update also adds another Do Not Track refinement, in essence, a “please track me” option. The simple check box previously only told sites you didn’t want to be tracked or gave them no indication of your wishes.

Mozilla, the non-profit maker of the browser, announced the new version in a blog post(Opens in a new window) today. “Mozilla developed the Social API to enable social providers to integrate directly into Firefox to make your browsing experience more social, customizable and personal,” the company said. “The Social API has endless potential for integrating social networks, e-mail, finance, music, cloud possibilities, services, to-do lists, sports, news and other applications into your Firefox experience.”

Mixi is a popular social network in Japan. Cliqz delivers news feeds and videos of interest to you, and you can enable the Firefox add-in at mozsocial.cliqz.com(Opens in a new window). msnNow scans real-time sources like Facebook, Twitter, Bing, and BreakingNews.com to keep you on top of the news cycle customized to your interests. You can install the add-in at this msnNOW page(Opens in a new window) so that you’ll never miss another Kardashian moment.

The new social plugins require an update to Firefox 21, which you can get at Mozilla’s Firefox download page(Opens in a new window).

A separate blog post(Opens in a new window), meanwhile, covered improvements to Firefox for Android. The mobile alternative browser now gets two new open-source fonts that should make reading Web pages easier and more enjoyable on those small mobile screens. It also increases support for emerging HTML5 standards, jumping to a score of 421 out of 500 on the often-cited HTML5Test.com measure. Firefox for Android is available via the Google Play app store(Opens in a new window).

For more, see PCMag’s review of Firefox and the slideshow above.