It's best to think of Facebook as a proof of concept. Yes, it has hundreds of millions of users, and yes, you can't ignore it as a distribution platform in 2012. But that doesn't make it a given that it'll be in a similar place of importance in 2015, or that you shouldn't be looking at the *principles* of social sharing now rather than any specific platform.

It's important for any content creator to keep control and ownership - and even more so in journalism, which is perceived to reflect the truth. The models around ownership are still shaking down, and while Google Search may be declining, we're likely to find new, social-aware models that will take its place. (They may also come from Google itself.) In the meantime, marketing studies have shown that the best way for your content to be shared is for it to be excellent. So, keep doing what you're doing, give people the tools to share, and be aware that you shouldn't put your eggs in any one platform's basket.