Google recently announced their new open source browser, called Chrome, via a comic book. Although slated for release sometime today, the link mentioned in the comic book (http://www.google.com/chrome) appears to be down is now up! The 38-page comic book is surprisingly informative, mildly entertaining, and certainly a unique way to release a new product, but don’t let the playfulness of the announcement fool you. Chrome has many important features, including a privacy-enhancing feature called “Incognito.”

Incognito is a user-visible feature that enables a private browsing mode. Private browsing is a relatively simple concept with tangible benefits to privacy. Under normal operation, a browser will store information about a user’s browsing history. Stored information could include sites visited, data downloaded, searches conducted, or even personal information entered. Under private browsing mode, that same browser simply doesn’t store this type of information. Essentially, a browser has no memory of what users do when private browsing is enabled.

Although private browsing is conceptually simple, it is not easy to implement because everything the browser does is affected by private browsing. Apple’s Safari browser has had a private browsing mode since version 2.0 (April 2005). Currently in version 3.1.2, Safari still is the only major browser to have a built-in private browsing mode. However, Safari’s private browsing mode isn’t perfect.

Private browsing was a planned feature for Firefox 3.0, but was dropped before the release because the developers “didn’t want to put something in that was half baked.” The Mozilla Wiki describes the current state of this feature and provides a link to a Firefox plugin called Stealther, which provides some private browsing features.

Microsoft has announced that they will include a private browsing feature, called InPrivate, in their next version of Internet Explorer. Microsoft’s effort seems to be even more ambitious than simply not storing data locally. For example, a Microsoft blog post describes a feature, called InPrivate Blocking, that would add the ability to block browsing information that would normally flow to third party sites.

Clearly, private browsing mode is not a trivial engineering task, but Chrome has some fundamental advantages over the “big three” that may simply make real private browsing easier to implement and maintain. Since Chrome will have Incognito on its first release there is less code that needs to be re-engineered to respect a private browsing mode. Also, Chrome uses a separate process for each tab, whereas a traditional browser only has a single process for all of its tabs. Multiple processes make it easier to sandbox tabs. As a result of these strict separations, it could be possible that Chrome would allow individual tabs to go “Incognito” while others act normally.

It is difficult to predict what sort of impact Chrome will have on the browser market, web application development, or Internet privacy, but if Chrome will have any impact, then it must compete with the “big three.” They are big for a reason, and a comic book isn’t going to solve that problem.

[ Update: Google has officially released Chrome at the following URL: http://www.google.com/chrome ]