They have been using Facebook as their main platform for the last years. Here's a status update from 17th of May, that is pretty much a farewell: https://www.facebook.com/splintermindpodcast/posts/3944220209029096?__tn__=K-R
I can't hold it against them. I might not have agreed with Brian that often, but I sincerely hope he does well in the future. It was clear that he had to stretch his schedule many times to make the show work.
On another note, does anybody know what happened to Thor666? Last time I checked Splintermind he wasn't on any of the episodes and without him, it wasn't even remotely the same. "Gun Hats"!