Can't speak for the author about Cactus, but in my experience if you want to integrate with a lot of services for comments on your blog, you can use a widely-im

Can't speak for the author about Cactus, but in my experience if you want to integrate with a lot of services for comments on your blog, you can use a widely-implemented protocol like webmention, along with a gateway like brid.gy for interfacing with centralized silos. Unfortunately Facebook shut down the brid.gy gateway a few years ago, but other silos still interoperate fine.