Using Google as a Verb – Acceptability and Usage

Both "that said" and "that being said" are common (possibly too common) and perfectly grammatical, and sufficiently formal as well. "Having said that" is also correct, but to be correct the subject in what follows must be whoever said that (usually "I"). For instance, you can say:

• Roses are usually red. That [being] said, they are also…

But you'd have to say:

• I like turtles. Having said that, I will now proceed to show…

That said, if you don't follow it up with "I", many people wouldn't notice anything amiss these days.

"That's been said" is a full sentence (edit: complete clause), and it only means "That has been said". Full stop. It cannot be used to introduce the rest of the sentence in the same manner.

Merriam-Webster has a whole list of suggestions:

• to book engagements via facebook
• to put something up on facebook
• to look up someone's personal information using Facebook
• to look someone up on a social website, to find one's information on a social website
• To upload a photograph to Facebook so that it may be viewed by others.
• To create an event entry on facebook
• To get on a facebook website.
• 1.to search for another person through the online directory know as facebook 2. to send a message through the online directory know as facebook
• To add someone to your list of friends on the "facebook.com" website.
• ...

Judging by the list, you can't predict which verb "to facebook" might or might not end up replacing. Right now, it's just a shorthand for many different things to different people.