A long time favourite software of mine, TAILS OS has trebled in popularity since the Snowden leaks last year.
Averaging about 4,000 boots per day last year the OS now, according to the OS’ anonymous developers, gets 12,000 boots per day.
The open source OS runs off of a USB stick that anyone can burn. It offers users a sterile environment to work from, it comes pre-configured with Tor Browser and routes all internet traffic through the onion router too.
When a user is finished with the OS they can shut down the computer and the RAM gets erased so that there are no traces of the user activity left over. The OS has all people in mind, including those whose homes are about to be raided by law enforcement, so a pretty nifty feature that is included is that ability to just pull the USB stick out of the machine and within seconds the machine is shutting down and wiping it’s RAM.
Find out more here: https://tails.boum.org/news/report_2014_05/index.en.html