Google's latest public display of cookie addiction revealed that while the ad side of Google enthusiastically embraces third-party cookies, the browser division is more hesitant. Here's how the five major browsers--Internet Explorer, Chrome, Firefox, Safari, and Opera--protect you from those third-party tracking cookies.But first: what's a tracking cookie? And why are they so important as a component of your online privacy? A tracking cookie can be used to follow people around the Web as they jump from site to site. Though your IP address or your HTTP request header's referral field can also be used to accomplish this, in part, tracking cookies allow for more accurate tracks. When you visit a page and there's no cookie present in the request, the server assumes that this is your first page visited. It then creates a random character string and sends it, as a cookie, back to you along with the requested page. That cookie then gets sent to all new pages you visit, and in turn creates a log of the cookie itself, all the URLs visited, and when you visited them on the server.
Of course, this has gotten extremely sophisticated over the years, but tracking cookies have been a security and privacy concern since the mid-1990s. The real-world equivalent is nothing less than being followed and analyzed for marketing purposes during each of your daily activities. Sarah Downey, an attorney and privacy analyst at the online privacy firm Abine, which makes the Do Not Track Plus add-on, said that online tracking-based privacy violations are fast approaching a critical mass. "The lack of online privacy is a huge problem, and with the Google news...it's getting worse and more complicated. Most consumers don't know what to do about it." Browsing cookie-free may sound like the easiest solution, but it also disables a lot of what's useful about the modern Web. Session cookie information, for example, will keep you logged in to a site even if you close the tab. This can be useful for computers that have only one user. So, the solution has to be nuanced to support the benefits of the modern Web while not throwing buckets of personal information at data aggregators. Except for Chrome, all browsers support the standard Do Not Track header. This tells Web sites not to track you, but it's respected by a tiny percentage of sites. You can also force Private Browsing to run all the time, which prevents cookies from being saved, though you can still be tracked via your IP address.
The strongest argument against blocking third-party cookies outright is that many sites will block content if they detect that your browser won't accept cookies. There are several good options around this, though recently I've been fairly impressed with the aforementioned Do Not Track Plus because it doesn't break social-networking tools. Looming just off-stage is mobile browsing, which is expected to grow tremendously this year. Privacy and tracking will be top concerns for a long time to come.