Google Talk chatback badge lets visitors to your blog or web page to chat with you whenever you’re signed in to Google Talk client or widget or Gmail chat. The visitors need not be signed up for Google Talk or a Google Account. The badge displays your online status your status message. This is just like the meebome service.
If you’re busy and don’t want to be disturbed by people clicking your badge, just set your status in Google Talk to ‘Busy’. This disables your badges and displays an unavailable status on your chatback badge while still allowing people in your Friends list to chat with you.
If you want to temporarily block the badge for a period of time, you can do so by clicking ‘Disable old badges’ and then click ‘Disable.’ in the badge creation page. After you block the badge, it will always display as if you are offline.
I think, the Google Talk Chatback Badge does not work with Google Apps domains. I could not find a way to set up the chatback badge for my teck.in Google apps id.