I was able to join Branch couple of days ago. I have not used it much personally but have been following a couple of branches.
I have even posted in some and have been invited for further discussions. Took me a while to realize why it is an interesting place to converse with people online…
You can embed links or twitter conversations to start the discussion. The bookmarklet they provide is very powerful and can ease the process of starting the conversation.
The most interesting element is that you can restrict the discussion to your choice of people while keeping it open to public. Guests can still chip in with their own points and you can approve them to join the discussion.
This makes it a lot better than alternatives like Google+ or even Facebook. You get a wider visibility with more control over your discussion. Google+ lets you share privately. But public posts would attract comments from spammers. There is no easy way to keep the discussion public but let select people to comment on it. Facebook has a similar problem with their own comment system. The closest that comes to Branch is Quora but they require very strict standards for starting a new discussion on their platform!
Branch of course is also tightly integrated with Twitter platform. Which makes it even more fun to use if you are active there.
Another powerful element is the ability to embed your branch on your own website like I have done below.
Here is a branch I started recently: