A new discussion platform called Branch announced today that it is leaving private beta and will begin sending invitations to the public. The startup aims to change the way people have conversations online — it allows users to start a discussion thread based on a post of their own or one from another site, and then invite others (via Twitter or email) to talk about it. Branch doesn't quite break away from the traditional thread style of discussion, but allows for a more focused experience by controlling who can participate and allowing users to create entirely new branches for individual tangents. The platform has received a lot of attention thus far in its quest to redesign online conversation, and if you're interested in checking it out you can sign up for an invite over at Branch.com.