What Is The Code To Put A Customers Name Into Newsletter?

...I feel stupid!

I got a very simple question, which I used to know the answer to, but no longer.

I would like to send a news letter and add a code which will add the customers name to the news letter.

Example:

Subject: Special Promotion
Message:

Hello {Customer}.

Blah Blah Blah Blah

Regards,
{StoreOwner}

What is the tag or code to do this? Thanks!