We can add social icons on custom vf pages using <social:profileViewer entityId="{!contact.id}"></social:profileViewer>.
You just need to pass the contactId or Account Id.
We will found one thing after this that is we don't see linkedin icon on custom page, because currently Linked in icon is not available in (Custom visual force page) as there is some issue in Linked in and salesforce contract.
Exm Code :
<apex:page standardController="contact">
<social:profileViewer entityId="{!contact.id}"></social:profileViewer>
<apex:detail inlineEdit="false" relatedList="false" title="false"/>
</apex:page>
