This is totally my personal opinion and you are free to comment the way you want.
I am myself a person who strongly opposes being invisible in chats like GMail or Yahoo! chat. But the reason why I am writing this is simple.
Off late, being invisible has become a craze (we call it "scope" in local slang ;-) ). This is no less than doing things in "STEALTH". When we ask people who usually do things in stealth like this, the reason they give are "There are too many distractions. There simply too many people doing non-sense things and just ping because they are jobless". These are the kind of responses we get. I agree that Invisible chat is indeed needed for these reasons. May we all have personal life and will have important work, where in we don't want ourselves to be distracted.
But these days some people always do things in stealth, whatever may be the situation. Oh, they have so much work? I never knew that they are the only people who have so much of work to do. They do it all the time and that too they don't want to be distracted all the time. Ohoh, I did not even know that, all those people who do not do things in stealth don't have work at all, as if!!!
I still cannot believe the above fact. The whole point here is that, those people who will be in stealth will be knowing whats happening in open. But people in open donot know otherwise. Just imagine what might be happening. How can we trust people who are stealth? They are like people who "Attack From Back". How can seriously trust those people? We don't know what they do at any moment. First of all its better to stay away from such kind of people, I feel personally.
Just imagine what may happen if everyone starts doing things in stealth. We just lose trust of everyone. No one trusts anyone else and a sort of cold war builds and we know the end. It just reminds me of a dialogue from Uppi's movie where he says, (warning: its in Kannada), *Aavanu ivana namballa, ivanu avana namballa, ottinalli neev yaaru uddara aagalla*. Meaning one person doesn't believe in the other, and the other person doesn't believe in this person, finally no one of you achieve anything.
But anyways after reading all these, if you still want to do things in stealth, here is how you can do for GMail chat in Pidgin. Note, the invisible status in Pidgin simply doesn't work in Pidgin for GMail chat.
1. Open the Buddy List.
2. In the menu, Tools->Plugins. Enable XMMP Console. Close the Plugin Window
3. In the menu again, Tools->XMMP Console->XMMP Console.
(See if your account in which you want to go invisible is selected if you have multiple accounts. )
4. In the text box, put the following XML snippet
and then press enter.
5. Done this is it. If this is not working on your version, now try changing the status to Invisible.
Finally, if you want to reset the above settings. Follow the same procedure but make <presence type="available"> in the above XML snippet.
-- Yours sincerely