Protect your privacy: Web browsing

Rich Mogull & Mike Rothman
17 September, 2011
View more articles fromthe author

The CEO of a major technology company once famously opined that, in the internet age, “You have zero privacy. Get over it.”

Some of us would rather not. We’d like to keep our personal information – whether it be what we share with friends on Facebook or our credit card details – under some control. We’d prefer not to let such information out into the wild, where it can be bought and sold and, often, used against us.

If you, too, are a privacy traditionalist, take heart: There are things you can do to make browsing, shopping, socialising and other online activities less of a threat. That CEO was right in some ways: We probably can’t keep all of our private information private. But we can certainly make accessing it harder for those who’d like to make it public.

Advertising networks

The risk  Ad networks such as DoubleClick and Quantcast track the sites you visit and the ads you respond to, to target ads at you.

How to protect yourself  A new Privacy pane in Safari 5.1’s Preferences better illuminates the websites tracking you. Rather than displaying a tangle of filenames, Safari now lists domains and the types of files – cookies, caches, plug-ins and the like – each has stored on your Mac. You can delete these items by domain or all at once.

To block cookies from third-party and advertising sites in Safari 5.1, go to Preferences > Security > Accept Cookies and set the option to Only From Sites I Visit. In older versions of Safari it is necessary to go to Preferences > Privacy > Block Cookies and set the option to From Third Parties and Advertisers.

In Firefox’s preferences, click the Privacy tab; from the Firefox will: drop-down menu, select Use Custom Settings For History; then deselect Accept Third-Party Cookies.

Go a step further by opting out of the major tracking networks. Visit the Network Advertising Initiative ( It checks your system for tracking cookies from participating ad networks, and lets you opt out of receiving them.

To browse completely under the radar, you’ll need some plug-ins. AdBlock for Safari (payment requested; and AdBlock Plus for Firefox (payment requested; block most ads and tracking; Ghostery (free; blocks tracking by more than 200 companies.

For complete browser control, try NoScript (free; for Firefox and the Plugin Customs extension (free; for Safari, but both disrupt how sites work.

As a final stop-gap, use a privacy tool such as MacScan (free; to sweep your system for lingering tracking information (as well as malicious spyware and Trojan horses).

Flash cookies

The risk  Local Shared Objects (LSOs) are small text files saved by Adobe Flash that function much like cookies, yet evade most standard privacy tools. LSOs have been a sore spot for Adobe users since 2009, when researchers showed they were being used extensively to track web surfers. These kinds of files are extremely common on major websites and are frequently used for tracking visitors.

How to protect yourself  Earlier this year Adobe introduced a new Flash cookie management option. Go to the Adobe Flash online settings manager to restrict how Flash stores LSOs. In the Global Storage Settings panel on that page, deselect the Allow Third-Party Flash Content To Store Data On Your Computer option (doing so will get rid of tracking). Setting the allowed storage space to zero will let you manually approve any requests for a new LSO.

For additional control in Firefox, we recommend the BetterPrivacy plug-in (free; This will delete all LSOs when you exit your browser or after a specified period of time. Note that if you do a lot of Flash gaming, you will want to allow LSOs for those sites.


The risk  Last year security researchers alerted Apple to a flaw in Safari. This meant that malicious users could get hold of your personal information, by exploiting Safari’s autofill feature that automatically fills in the blanks in web forms.

How to protect yourself  Previously the only fix was to disable the ‘Using info from my Address Book’option in the AutoFill preferences pane. A new Private AutoFill feature in Safari 5.1 doesn’t automatically enter your personal info into web forms until you give the OK. You can choose the specific information to be filled in. The browser asks your permission and even lets you specify whether to pull information from Address Book or Outlook.

Leave a Comment

Please keep your comments friendly on the topic.

Contact us