Donnachadh Gough was, but I don't see Aoife Clancy in the listing of the line-up in the Celtic Connections listings on their website.
I think Jos is probably right that it's a one-off on the night, whether you're a Facebooker or not........but I could be wrong. One of our local folk clubs has done similar, (also via Facebook), and I don't remember being able to do "catch-up" afterwards.
One thing that did come up as the evening went on, was the opportunity to sign up for alerts for further live-streamed concerts: this just popped up in the comments column: guess you can do this through Celtic Connections' own Facebook page.