@Vivainio tweeted this, looks pretty cool as a nextgen forum sw alternative: http://www.discourse.org Free & F/OSS too it seems. I haven't yet done a in-depth comparison between it & VB though.
What are the minimum browser requirements? Discourse is a JavaScript application designed for the next 10 years of the Internet, so the minimum browser requirements are high: Internet Explorer 10+ Google Chrome 24+ Firefox 14+ Safari 5+ We do officially support Internet Explorer 9, but some functionality will be unavoidably broken. What tablets and phones are supported? Discourse was intended from the beginning for future high resolution displays and ubiquitous touch devices. Mobile Safari, iOS5 or later Mobile Chrome, Android 4+ or later Mobile IE, Windows Phone 8 or later However, we have not optimized for small screens yet – so for now, the best Discourse experience will be on 7" or larger touch devices. Should I switch to Discourse right now? Probably not. Discourse is brand new. Discourse is early beta software, and likely to remain so for many months. Please experiment with it, play with it, give us feedback, submit pull requests – but any consideration of fully adopting Discourse is for people and organizations who are eager to live on the bleeding and broken edge. There is tremendous technical and sociological friction to change in any established community. Consider carefully whether your community is willing to adopt such a big change. Perhaps start a discussion about even the possibility of such a change well in advance. We believe Discourse currently makes the most sense for new discussion communities. In some rare cases communities may have a discussion platform that they intensely and actively dislike, to the point that they are willing to throw the whole thing away and start over.