Can you provide a little more information? Where/how are you triggering the email, as that's where the information will need to be pulled in. If it's not provided in the macro context that is passed to the email engine, then it can be added, but knowing your processes will help us understand what that macro context is already.
In general, if you ahve any reference to the blog post (documentID, nodeID, node alias path, etc) you can usually pull up values through macros such as {% Documents["/MyNodeAliasPath"].GetValue("SomeValue") |(identity)GlobalAdministrator%}