A couple weeks ago, Rand Fishkin tweeted out a link to new guidelines that Google published for adding social profile links to your Knowledge Graph card:

I took a look at the documentation, and the markup is pretty simple. It’s basically Schema.org markup that you add to your main website (the one linked to your Google+ page) and you just add the additional markup to your social profiles in the following format:

Intrigued, I added it to several of the sites that I manage that display Knowledge Graph cards in the SERPs. About a week later, I saw the following appear for the KG card for my dance team’s website.

You can see in the bottom left the new social link to our team’s LinkedIn page. But it doesn’t show any links to any of the other profiles I linked to.

It turns out that if you read the fine print in the documentation, Google will only display social links for *VERIFIED* profiles on social networks that have verification features. That means on sites such as Facebook and Twitter, your social links won’t show in the SERPs unless you have a magic blue checkmark. Also, since the markup needs to be on your official site, in its current form it will only work for Pages and not personal Profiles.

So that’s my experience so far with adding social links to Knowledge Graph cards. The other two sites that I added the markup to aren’t showing any social links yet, so I may need to revisit the code or it may be the case that I just need the social profiles verified.

Addendum:

A list of social networks that appear in Google Knowledge Graph cards, and which have a verification feature:

• Facebook – Requires Verification
• Twitter – Requires Verification
• Google+ – Requires Verification
• MySpace – Requires Verification
• Instagram – Requires Verification
• YouTube – Requires Verification
• LinkedIn – NO VERIFICATION REQUIRED
• Pinterest – Does not appear in Knowledge Graph?
• Tumblr – Does not appear in Knowledge Graph?