pixls.us currently uses the rss parsing + embedding support shown in @eviltrout 's blog post. In the current design only one site can embed back. One option to fix this would be to have a mapping category->site and allow embedding based on that mapping. In the case of Pat, he thought about sharing his instance with the libre graphics community. For me personally I would love to have discourse as common commenting platform over all opensuse.org sites. The mozilla team was discussing similar things here.