There are many different models of auto blogging. And there have been products selling blog and ping programs for years.
And it's been a game of cat and mouse with Google.
I remember one of the first products found content based on a keyword, posted it to your blog, and then pinged your blog.
It ran constantly and these blogs rose to the top of the search engines overnight.
Then these auto-post blogs were discovered and banned.
There are now a number of auto-blog products out there that go out and scrape content and post them to WordPress.
They work really well. They can get great rankings dependent on your keywords but here are the problems as I see it:
1. Many of them scrape content without attribution. This is stealing.
2. Google is aware of the scraping of content and is currently building a new model that will exclude sites built on this model.
Of course it's easier to scrape content than create your own.
There just has to be a better way.