BGPSEC & soBGP

I came across this article on /.: http://www.networkworld.com/news/2009/011509-bgp.html?page=1 I'm not too familiar with security of routing protocols, but it became immediately evident as I read this article that much of the work has been accomplished with soBGP. I'm wondering why there is a new initiative for another technology to secure BGP. -- Naveen Nathan