A short tutorial on how to run multiple firefox with completely different session, cache, data, installed plugins, etc. Just like when you are doing a fresh browser installation. But instead of installing more browser, you just need a single firefox installation and run it in multiple independent instances. Which allows you to login to multiple website accounts simultaneously (at same time).
With this method, you can log on multiple account in google, facebook, twitter, etc. and the only thing they can track about it is just the IP address similarity (not a problem if you are also using proxy).