Including commenting system please. :-) Is there any way comments could be shared across LinkedIn, HN, blog, et al, all visible at the blog itself? And where

Including commenting system please. :-) Is there any way comments could be shared across LinkedIn, HN, blog, et al, all visible at the blog itself? And where to find good themes for static site generators. Am willing to pay. Theme for me is just as important as picking up the tech. stack.