I have a gmail contact which I don't want them to see me online - but I still want the others contact see me online. A feature similar to stealth setting in Yahoo. How can I do that with gmail/gtalk?
Thanks to help from user, blocking user as offically said here is the answered.
Blocking someone will prevent him or her from talking to you, and vice-versa. Blocked users can't see when you're signed in to Google Talk, and you won't see their status in your Friends list, either. If you decide you'd like to communicate with someone you've blocked, just unblock them.