Update to Debian documentation
On Debian (I tested on stable (wheezy), testing (jessie) and unstable (sid)), if a user follows the instructions on https://www.torproject.org/docs/debian.html.en, the user still ends up with the Debian version of the package, not the Tor Project repo version. The user must use APT preferences (apt pinning) to prefer the Tor Project repo to the Debian repo in order to ensure that the tor package is installed from Tor Project's repo and not Debian's.
The steps I took to remedy this are as follows:
If the file does not exist, create the file "preferences" in /etc/apt/ with the contents:
Package: * Pin: origin deb.torproject.org Pin-Priority: 1001
Package: * Pin: origin Pin-Priority: 500
This should prefer any package in the Tor Project Debian repo that is also in the main Debian repository, even if the package in the Tor Project repo constitutes a downgrade (in the event of a necessary reversion of a broken package).
The 500 for the default Debian repo is just a suggestion. 500 is the default pin priority for the main archive. The value jumps to 990 if the user specifies a target release using apt-get -t so overriding for an individual package functions like normal.
Hope this helps.