Private Browsing is an open source portable app that works in conjuction with your portable Firefox copy. While Firefox already has a private browsing mode that will not save what sites you have visited, cookies, passwords, downloaded items or search entries and run completely in RAM memory not caching files in the hard disk, Private Browsing by Portableapps comes preconfigured with all of that and a couple of privacy plugins, FlashBlock and AdBlock Plus using the EasyPrivacy tracking list to block scripts and invasive sites.
After trying Portableapps Private Browsing app I found few advantages over configuring your Portable Firefox browser yourself, other than saving time. The app could also be improved disabling the default setting of sending data to Mozilla about your browsing “so that they can improve your experience“, with the actual configuration you will be prompted about what you want to do, another setting that should have been changed are the default Google and Yahoo search engines, the app would be better off unfolding non tracking search engines like StartPage or DuckDuckGo, you can change them yourself but it fails Private Browsing aim of reducing privacy configuration to zero.
The only unique features this app appear to have are that it will ignore local plugins, for example, if the computer you are working on has Java and Flash installed, the plugins will not work with your portable browser, and Firefox portable will not store a profile listing what sites you visited. Check out my list of the best Firefox addons for computer privacy if you need ideas to set up a custom private browser and add them yourself manually.