Go invisible in Gmail chat

One of the most missed feature of the Gmail users was about the Chat within the Gmail. Whenever people used to login to check their mail to Gmail, they also used to signin to Google Talk present within. Later Google added the feature to sign out of chat only while checking mail. But I think this was not the solution wanted by many. There are many who wants to be logged in but 'invisible' . And many IM client including Windows Live Messenger has this feature since long. And even Google Talk client also does not have this feature apart from built in Gmail chat.

But now the Google chat in Gmail has provided this feature where while checking the mail, one can also sign into Google chat as Invisible with a view of people available for chat. I think this feature has been recently added to Gmail chat, while its still not provided in Google Talk desktop client.

So for providing such features, I think Gmail is still in Beta? When will Gmail come out of Beta? Is it the one which is having the Beta tag for the longest duration ?