I think META like many other "service providers" don't yet realize, that it's becoming trivial to roll your own and all we need is a protocol. And arguably there are many. You can then use your existing social graph (anyone remembers this term? lol) to chat. Your mom and granddad won't roll their own, but publishing an open service that uses FB openID and API while delegating to the open protocol is really not that hard. Browser local storage may not be ideal, but it's a good placeholder until something better can be implemented.