Add-ons that help browsers block Web trackers

Patrick Marshall

Browsers provide a fairly good first line of defense against Web tracking, but to protect against beacons, JavaScript trackers, and widgets, you need more.

Third-party browser add-ons and applications can provide better defenses against websites that want to follow your online activities.

In last week’s Top Story, “You’re being followed! How to block Web tracking,” I discussed the anti-tracking tools built into the three top browsers: Firefox, Google Chrome, and Microsoft’s Internet Explorer.

Most browsers’ tools let you manage the simplest form of tracking — cookies. But trackers use many other techniques for following your online activity, including beacons, bugs, IP-address linking, scripts, tracking pixels, widgets, etc. There are literally hundreds of tracking technologies in use, all designed to record your browsing habits and interests.

Why so much effort to find out what you do online? Targeted advertising is the most common reason. Sites are paid for ad space — but they’re not paid much. So websites use what they know about you to display ads that you’re more likely to click. And the more they know about you, the more effective the ads will be. That’s the theory, at least. It’s why you can go to a shopping site and look up a product, then have ads for that product follow you wherever you go on the Internet.

Most add-on anti-tracking products either attempt to detect scripts, beacons, and other tracking technologies or keep lists of tracking sites to block — and sometimes both. By and large, these products are install-and-forget browser add-ons. Unless you want to exempt a specific tracker from being blocked, you might never even call up the blocking app’s configuration utility.

Tracking blockers also offer another, smaller, bonus: users will often notice slightly faster browser performance. Tracker code typically runs each time you load a webpage. Blocking that code lets your browser move on to more useful things.

A tour of popular anti-tracking products

For this article, I took a look at three leading products: Disconnect, DoNotTrackMe, and Ghostery. If you do a Web search for tracking blockers, these three typically come up most often.

Before getting into the details of these products, I’ll say that it’s difficult to compare how thoroughly these products block trackers — primarily because they report on trackers in different and often confusing ways. (For my tests, I had each tracking blocker scan the same four webpages.)

Disconnect, for example, reports the detected number of separate requests to external domains. On the New York Times homepage, it reported 33 requests from nine domains. Ghostery, on the other hand, reported 11 trackers but not the number of individual requests.

The names of trackers don’t always match up, either. One blocker might report Google as a single tracker, while another will break it down by the individual Google products. You might see DoubleClick and not know it’s a Google product.

Also keep in mind that these products are constantly updating their tracker databases. So Ghostery might find the most trackers on a webpage one day, but DoNotTrackMe finds more the next day. Also, don’t assume that any tracking blocker is 100 percent effective. Just as virus writers are always changing their code to evade detection, so too are trackers evolving their methods of tracking.

Your choice of an anti-tracking app might also be determined by the browser you use. In short, not all blockers work with all browsers.

Finally, there are inherent frustrations when using these products. They will block some things you don’t want blocked! You will find that some websites no longer work as you expected. If the site is one you frequent, you’ll need to use the program’s exemption tool to fix the problem.

Disconnect: A top choice — unless you use IE

After reviewing the three anti-tracking tools, I continue to use Disconnect (site). It’s easy to use but also provides comprehensive reports. It has only one drawback: it works with Chrome, Firefox, and Safari — but currently not Internet Explorer. Disconnect is free, though donations are strongly encouraged to help defray maintenance and development costs.

At one time, Disconnect looked for tracking signatures and behaviors in order to block tracking sites. It now uses a single form of tracker detection: intercepting all requests to contact third-party domains. It then checks whether those domains belong to a tracker. By default, it also denies all requests except those requesting webpage content. The Disconnect site claims over 2,000 third-party sites blocked.

Disconnect’s display is easy to navigate, once you know what you’re looking at. It adds a browser toolbar button — a “D” with an overlaid green square that contains the numbers of domain requests from the page you’re currently visiting. Click on the D, and Disconnect pops up a full report (see Figure 1).

Disconnect report

Figure 1. Disconnect reports the number and type of trackers on a New York Times page.

The top of the report has a bar containing the number of requests by the three most common tracking sites: Facebook, Google, and Twitter. All other tracking sites are listed below the bar, in four categories: Advertising, Analytics, Social, and Content. Clicking a category displays an expanded list showing which specific trackers were sending requests. You can quickly block or unblock a tracker by simply clicking its associated checkbox.

Below the reports is an Options section with four tools. The first lets you toggle the currently loaded site between Whitelist site and Blacklist site. This enables or disables all trackers on that site with a single click.

Next, you’ll find a Secure Wi-Fi checkbox. Checking it encrypts data transmissions whenever possible. The feature currently works with Facebook, Gmail, Google, LinkedIn, Twitter, Yahoo, and YouTube.

The third option — Visualize page — graphs the requests coming from the site you’re visiting. I’m still not sure what this feature actually does, because it was never available for any of the pages I visited.

Finally, there’s a Secure search feature that’s not explained and not yet enabled.

Disconnect also includes a dashboard with essentially feel-good bar charts indicating how much time and bandwidth you’re saving as a result of using Disconnect and how many requests have been blocked. Since no actual numbers are provided, this feature isn’t of much use.

DoNotTrackMe: Making tracker blocking simple

Abine’s anti-tracker is truly plug-and-play. DoNotTrackMe (DNTMe; site) runs on Chrome, Firefox, Internet Explorer, and Chrome — and there are no initial settings to configure. About the only user action is to block or unblock specific trackers, if desired. Abine claims that DNTMe blocks over 600 trackers.

A DoNotTrackMe FAQ states, “By default, DNTMe is set to block all tracking.” That wasn’t my experience. On many sites, I found a number of trackers unblocked, though I was able to manually block them. When I opened the product’s configuration utility and unchecked “Use Abine suggestions,” all trackers were subsequently blocked.

Like most anti-trackers, DNTMe puts an icon on the browser’s toolbar, along with an overlay that shows the number of trackers detected on the current webpage. Clicking the icon summons the app’s report display.

A bar at the top of DNTMe’s display shows the total number of trackers on the current page. The next bar down shows the social-network trackers that are present, and the bar below that shows tracking companies that are present. Its tracking-companies report, however, doesn’t distinguish between advertisers, analysis companies, and content providers (see Figure 2). In some cases, that might make it more difficult to decide whether to block or unblock a given tracker.

DoNotTrackMe report

Figure 2. DoNotTrackMe's report provides basic information on trackers.

DoNotTrackMe is free, but the entire bottom half of the DNTMe display is devoted to ads for paid Abine products. DNTMe should appeal to users who prefer simplicity — who don’t want to tune their anti-tracker and aren’t curious about the details of who’s being blocked.

Ghostery: Detecting tracking technologies

Evidon’s Ghostery (site; free) takes a somewhat different approach to rooting out trackers. It focuses primarily on detecting JavaScript code that’s used by beacons and certain other tracking technologies. Previously, Ghostery didn’t examine requests sent out to third-party sites. At this time, the company has not responded to my query into whether that’s changed. The Ghostery site does claim over 1,400 trackers tracked.

Whatever its methods, Ghostery did a solid job of snagging trackers. I found only a couple of trackers (out of several dozen) that were seemingly missed by Ghostery but caught by the other two products.

And Ghostery’s interface is exceptionally easy to use. The toolbar button shows the number of trackers found on the current page. In Firefox, the report box lists each tracker and gives its category: advertising, analytics, social-network sites, or content providers. If you want to block or unblock a tracker, it’s a simple matter of using the slider button next to the tracker’s name (see Figure 3). Ghostery’s report box has a simpler format in Chrome (see Figure 4). To manager trackers, you click the Edit Blocking Options button and checking the box to the right of the tracker’s entry.

Ghostery Firefox report

Figure 3. Ghostery's new look in Firefox

Ghostery report

Figure 4. In Chrome, Ghostery starts with a simple list of found trackers.

Below the list of trackers are several buttons. One large button lets you whitelist specific trackers on the current webpage or the entire site. Another button pauses tracker blocking — a handy feature if you want to test whether Ghostery is preventing some webpage function that you want active.

Ghostery supports the broadest range of browsers — not only the big four, but also Opera. There’s also a Ghostery version for iPhones and iPads. On the other hand, it currently won’t work with Windows 8, IE 10, or 64-bit Windows. Also be advised: Before you can install the current version of Ghostery on IE, you’ll need to make sure there are no earlier versions installed. In IE, click the gear icon and select Manage add-ons.

Combined defense: These tools are one line of defense against sites that want to know what you do and where you go on the Internet. The other line of defense is configuring cookie controls in all of the browsers you use.



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All Windows Secrets articles posted on 2013-08-08:

Patrick Marshall

About Patrick Marshall

Patrick Marshall is a regular technology columnist for The Seattle Times. He has also written for Government Computer News, InfoWorld, PC World, the Congressional Quarterly, and other publications.