Plug-ins for Privacy: Firefox Mobile and More


If you’re a desktop browser nerd, these are some very exciting times. Electrifying new releases of Firefox, Chrome, Internet Explorer, and Opera might have you absolutely giddy. I know I can barely contain myself. There is, however, a world beyond our safe desktop browser walls. It’s the world in which your children will very likely grow up. It’s a world that fits in the palms of little hands. It is, of course, the world of mobile phones, the fastest-growing Internet access vector. But rarely is the question asked: Is our children learning … to be private on their mobile phones?

[This is a guest post by Cyrus Nemati, Web Producer for the Center for Democracy & Technology]

The truth is, privacy has been a secondary concern of mobile browsers so far. Mobile browsers sacrifice a lot of the functionality, privacy tools included, of their desktop brethren simply as a result of space constraints. My desktop copy of Firefox is utterly packed, a mess of 52 plug-ins (no, it doesn’t crash … too much), but the browser is still as usable as the day it was installed (okay, maybe a little slower … or perhaps a lot). If those same extensions were applied to a mobile browser, you wouldn’t be able to see the browsing window at all. With toolbar upon toolbar, it would be a nightmare akin to using your grandmother’s copy of Internet Explorer 6. Mozilla, however, has come to save the day, with its Firefox Mobile browser.

Firefox Mobile, formerly known as Fennec, an adorable fox species, was designed to be the Firefox experienced distilled into a mobile browser. The features of the 4.0 version of the mobile browser are very comparable to the desktop version, with a speedy rendering engine, syncing, and add-ons (a.k.a. plug-ins).

Most mobile plug-ins, as one might expect, are designed to make browsing the web on a mobile device a less painful ordeal. Privacy-related plug-ins are likely to cause inconvenience, but the good developers at Cleary and Adblock were willing to take a shot at making usable privacy plug-ins for mobile.


Developers have their work cut out for them when making a mobile-browser plug-in. Users want plug-ins to add specific, useful functions to their browser, but they don’t want their regular browsing to be impeded. Many mobile plug-in developers take this concern somewhat too seriously, and make their plug-ins’ functions almost completely invisible. This is unfortunate when a plug-in adds unique and necessary tools for privacy, which is the case with Cleary.

What Cleary does is add a few new privacy-related features to Firefox Mobile. One of the more enticing features is its mobile version of the Do Not Track header, which was originally an addition to the desktop version of Firefox that transmitted a special HTTP header that told advertisers not to track the user. Cleary also gives you the ability to clear more information from your browser than a stock browser installation would (and with a greater degree of control) when you use the “Clear private data” setting, and it provides a setting allowing you to clear data every time Firefox is closed.

Where Cleary stumbles, however, is in its presentation. Its fine-grained control is hidden in Firefox Mobile’s preferences, and even there, the only indication of its existence is an arrow next to the “Clear private data” section. Cleary’s other functions — enabling Do Not Track and enabling clearing of information upon closing the browser — are hidden under the add-ons option screen. Since these are very likely to be one-time settings, the smart thing for Cleary to do would be to present them upon users’ first installation of the plug-in. As it is now, users receive no clear indication when Cleary is ready for set-up, not to mention how to set it up, so many users may unknowingly neglect to activate the new functions at all.

Privacy Power (5/5)

Cleary fixes Firefox Mobile’s omission of the Do Not Track header, which is worth more than the cost of installation (free) alone, especially as more advertisers start honoring the Do Not Track HTTP header. The addition of further controls to the browser’s clearing functions is a nice bonus.

Ease of Use (2/5)

Cleary clearly (say it 4 times quickly and you’ll sound like a chicken) needs some sort of initial setup wizard, preferably of the gentle Gandalf variety.

Uniqueness (4/5)

Cleary has the great advantage of being first in a new market. Firefox Mobile does not yet support the Do Not Track header, and it could use a bit more power in the privacy settings department.


I’ve written about Adblock before, specifically about its Chrome incarnation. This isn’t the same Adblock jammed into a tiny screen, though — at least not where the interface is concerned. Once you add Adblock to your Firefox Mobile installation, you’ll be hard-pressed to notice any changes. It is also very easy to use, although it doesn’t allow the user quite as much customization as the desktop version does.

With its seamless execution, Adblock is an excellent mobile plug-in. You really can’t tell that Adblock is working, because potentially privacy-invasive advertisements are simply gone, like Charlie Sheen’s acting career (zing!). You’re not left with gaping holes in web pages, either; the places where ads would have appeared are gone as well. (This can be pretty disconcerting, actually. I re-installed the plug-in twice because I thought it wasn’t working. It’s almost *too* clean.)

Additionally, Adblock’s mobile user interface is quite simple; only a couple of interactive elements are available. You can deactivate Adblock on a site by tapping its status bar in Site Options, and you can adjust what lists it uses, as well as whether or not it collapses blocked elements, in Extension preferences. Bada-bing, bada-boom.

Mobile Adblock, however, has significantly less fine-tuning power than it does on the desktop. One can’t add to Adblock’s filter on the fly, nor can one eliminate page elements at will (I can’t imagine, however, how this could be achieved on a touchscreen. Let’s just say Adblock gets a pass on that).

Privacy Power (4/5)

As with the desktop version, if you trust Adblock’s lists, you trust that Adblock is keeping you relatively private.

Ease of Use (5/5)

As I mentioned, I didn’t even know when Adblock was properly installed. Adblock does its job quietly and never complains or asks for any user input.

Uniqueness (5/5)

Adblock is the most complete, desktop-level mobile privacy browser plug-in available. It doesn’t get much more unique than that.

I’m really excited about the plug-in future for Firefox Mobile. One of my favorite plug-ins, NoScript, is in the works, and I’m certain more privacy-oriented plug-ins are on the way. Privacy may not be foremost in the mind of the mobile browser user, but user control is something we all want. Check out CDT’s Take Back Your Privacy page to find out more ways to protect your privacy.

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