Google Talk has a feature that auto subscribes some contacts that I have been talking with. It's a ok feature, but sometimes I'm not interested in having the person view my online status. How can I prevent this? Do I need to block him or is it good enough to remove him from contacts?
GTalk in Gmail
You can't set individual available/invisible status for each user in your list. What you can do is either block/unblock individual users whenever you need to (this means they can't contact you while they are blocked), or turn off the auto subscribe feature and manage the list manually.
To turn off auto subscribe:
From the man page: http://www.google.com/support/chat/bin/answer.py?answer=29795
To block/unblock a user:
Unblocking a contact:
From the man page: http://www.google.com/support/chat/bin/answer.py?hl=en&answer=161879