This is probably the best overview out there: http://brehaut.net/blog/2011/ring_introduction http://brehaut.net/blog/2011/ring_introduction, though it doesn't m

This is probably the best overview out there: http://brehaut.net/blog/2011/ring_introduction http://brehaut.net/blog/2011/ring_introduction, though it doesn't mention the new kid on the block, Noir (http://www.webnoir.org/ http://www.webnoir.org/)