Is it possible to integrate Wordpress *posts* and social media (Facebook, Google+, Twitter)? [closed]

Question

Is there a plugin available that will automatically post an excerpt of a blog post (perhaps up to the more tag) to specified social media groups/pages. So, for example, on posting an excerpt would be posted with a 'Read more' link to a user-defined Facebook group, G+ page and, possibly, twitter feed?

If not, is there a method for automating this process? Or is copy>paste the only realistic option?

(I know that Dsiqus provides the ability to link comments and social media but this functionality doesn't extend to posts, as I understand it.)