How do you create a variable from hook_preprocess_page() that will be available to a node template?
How do you create a variable from hook_preprocess_page() that will be available to a node template?


You cannot.
The parameter passed to hook_preprocess_page() (what you define as &amp;$vars) is not the same parameter passed to hook_preprocess_node(), which means that if you set $vars['social'] in the first, it is not passed to the latter. If you need to pass a value to the node template file, you need to set it in hook_preprocess_node(), or hook_process_node().