Set Share Preview Content For Facebook, Google+, And More
When I share pages from people’s sites and the preview is useless, it really annoys me.
Here are some resources to help you figure out how to properly set the meta tags on your page so they can be shared more effectively by your audience.
Facebook https://developers.facebook.com/docs/share/
Google+ http://support.google.com/webmasters/bin/answer.py?hl=en&answer=1211158
LinkedIn https://developer.linkedin.com/documents/setting-display-tags-shares