Aug 24, 2010 09:29 GMT  ·  By
Private Browsing is popular with Firefox users at certain points during the day
   Private Browsing is popular with Firefox users at certain points during the day

Private browsing modes are a common sight in browsers these days. And, while the feature is an easy target for tongue-in-cheek jokes, private browsing serves a very useful purpose.

Now, thanks to new data from Mozilla, we can put an end to some of the speculation surrounding the feature and get a real grasp of how people are using Private Browsing.

Mozilla doesn't provide any data on why Private Browsing used, just when and for how long, but it's still an interesting insight. Using the Test Pilot add-on, Mozilla researchers were able to determine that there are a few moments during the day when more people use Private Browsing.

"Private Browsing was introduced in Firefox 3.5, giving users the option of browsing the web without keeping track of their history. A recent Test Pilot study recorded – among other things – the time users activated Private Browsing, and the time they deactivated it," Hamilton Ulmer, from the Mozilla Metrics team, wrote.

Mozilla underlines the fact that no data is recorded during Private Browsing. Test Pilot enables users to join various experiments and surveys Mozilla is holding. It is entirely opt-in and the users are in control of the data collected and submitted.

From the study, Mozilla learned that there are several times during the day when users activate the feature. The first and biggest spike is during the lunch break, between 11 AM and 2 PM, when most people go into Private Browsing.

This makes sense, being at work, users may want to do a bit of personal browsing during their breaks, maybe check out Facebook and the likes, without leaving too many traces.

The second big spike is just after most users leave from work and school, at 5 PM. It's interesting that this spike is very significant yet very short, it's just for a small while after 5.

Another, smaller spike is just after dinner, when users again activate Private Browsing in mass. The final spike is an hour or two after midnight. We'll leave it to you to speculate on why that happens.

When they do activate Private Browsing, most people don't use it for that long, 10 minutes seems to be the sweet spot.

"The 25th percentile stays on for about 4 and a half minutes, the 75th percentile around 22 minutes, and the median stays in for about 10 minutes. This trend appears to hold over the entire course of the day, with the notable exception of 5pm," Mozilla explained.