Se puede usar para evitar los proxys que bloquean el messenger de hotmail, en general puede saltar todos los bloqueos de los proxys, especialmente esas empresas cuyos servidores proxys tienen todos los puertos bloqueados (por lo general dejan uno abierto), para lograr este cometidos usa la red tor.
Description:
Vidalia is a cross-platform controller GUI for Tor, built using the Qt framework. Using Vidalia, you can start and stop Tor, view the status of Tor at a glance, and monitor Tor’s bandwidth usage. Vidalia also makes it easy to contribute to the Tor network by helping you set up and manage your own Tor server.
Vidalia runs on most platforms supported by Qt 4.1 or later, including Windows, Mac OS X, and Linux or other Unix variants using the X11 window system.
You can view some screenshots of Vidalia or go straight to the download page.
http://vidalia-project.net/