Blogging tools have had posting APIs since the beginning of the art, starting back in the mid--late-90s. Blogger, WordPress, Tumblr, they all have them. As does Twitter. It doesn't seem to have hurt them. Yet Google-Plus doesn't have a posting API. If it did, I would publish my stream
there, and they would have some good sticky content that they don't now have. I think they should do it.