Google's Secret Command-Line Parameters

There are a few secret parameters you can add to Google Talk and make it function differently.

The most important, I think, is /nomutex, which allows you to run more than one instance of GT.

Here are the others:

/nomutex: allows you to open more than one instance of Google Talk
/autostart: when Google Talk is run with this parameter, it will check the registry settings to see if it needs to be started or not. If the "Start automatically with Windows" option is unchecked, it won't start.
/forcestart: same as /autostart, but forces it to start no matter what option was set.
/S upgrade: Used when upgrading Google Talk
/register: registers Google Talk in the registry, includig the GMail Compose method.
/checkupdate: check for newer versions
/plaintextauth: uses plain authentication mechanism instead then Google's GAIA mechanism. Used for testing the plain method on Google's servers.
/nogaiaauth: disables GAIA authentication method. The same as above.
/factoryreset: set settings back to default.
/gaiaserver servername.com: uses a different GAIA server to connect to Google Talk. Used for debug purposes only, there are no other known GAIA servers.
/mailto email@host.com: send an email with Gmail
/diag: start Google Talk in diagnostic mode
/log: probably has something to do with the diagnostic logging
/unregister: ?
/embedding: ?

To add these, open up your GT shortcut, and where it says "Target:" add one or more of these inside the quotations, but after the .exe part.