ll of you definitely have Gmail account and you might have used chat option that is available not only in Gmail but also in Gtalk and Orkut. Here I will discuss about Bug in gmail that enable us to detect invisible user in chatting. Some times while chatting we need to be invisible may be because of lack of time to chat or you want to avoid some one! In the same manner the person to whom you are chatting may also avoid you. But after reading this post he will not be more longer to do so.
Open your gtalk app and type this email address in top search textbox
Click the profile, it opens in new window as usual
Click on the down arrow button in the top right corner of the window, and you can see Go off the record link there.
And type any chat, say “hi”
You will get a red text showing the “person is offline , can’t receive the message right now ” implies the person is offline
If this message does not appear, it means the user is invisible