A peek into private browsing in the next Firefox 3.1 beta

It's a race now to be the first to implement an evidence-proofing feature in an RTM of a Web browser. The fellow in charge of making it work for Firefox made his suggestions known over the weekend, and he wants to keep things simple.

It's rare that Mozilla Firefox finds itself in the role of playing catch-up in the feature department. But with a special private mode that suspends the recording of cache and history data already showing up in both Microsoft Internet Explorer 8 and even the earliest betas of Google Chrome, the open source developers at Mozilla are stepping on the gas for a feature they've actually considered for several years.

The problem, up to now, has been less of a technical one (intentionally not doing something is pretty easy to program) than one of presentation: How should the browser inform its user that he's browsing the Web in private? As developers have commented in the past, you can't exactly wave a big red flag that screams, "PRIVATE" without attracting attention. On the other hand, something needs to inform the user that his online tracks are being ignored without being so discrete that he can't tell the difference.

In a blog post yesterday, Mozilla contributor Ehsan Akhgari -- who is assigned the Private Browsing project for Firefox -- gave other developers their first peek into his take on the feature. While Chrome (which has yet to see a "final" release) presents a prominent cloak-and-dagger icon to adorn its private browsing windows, the latest nightly build of Firefox 3.1 (not an official public beta) shows a less flashy, more discrete approach: one which may very well not be the one finally adopted.

We tried the nightly build produced early this morning by Mozilla, on an XP Professional SP3-based virtual machine. For now, the system is fairly simple: From the Tools menu, you select Private Browsing. Firefox will remind you that it will save your open tabs before entering Private Browsing (PB) mode, because unlike the case with the current IE8 Beta 2, the private window will not open separately from the non-private one. Rather, your recorded browser session closes and your private one begins, with a little warning telling you that nothing is being saved for posterity.

"Private Browsing aims to help you make sure that your web browsing activities don't leave any trace on your own computer," Ahkgari wrote yesterday. "It is very important to note that Private Browsing is not a tool to keep you anonymous from websites or your ISP, or for example protect you from all kinds of spyware applications which use sophisticated techniques to intercept your online traffic. Private Browsing is only about making sure that Firefox doesn't store any data which can be used to trace your online activities, no more, no less."

While the session lasts, the only indication the user receives that it's private is in the title bar of the window, where the (Private Browsing) warning appears. Earlier, contributors suggested other changes to the front end, such as perhaps replacing the page icon on the title bar or altering its color; but with that icon also serving the purpose of reporting the validity of a signed and authenticated site for an encrypted session, any extra embellishment there could be difficult for users to interpret.

Some contributors still want to see more pizzazz to this feature; but the problem is, the developers are limited by their own self-imposed constraints about the extent of visual changes they'll allow between Firefox 3.0 and 3.1. If the feature changes more than just the appearance but also the functionality of the browser any more than the current nightly build suggests, then private browsing could be postponed altogether -- and in the feature race, Mozilla may not be able to afford further delays.