I think you can put @text(@username) in place of xxx , if you are using formula to send mail, so that whan a person reads he/she gets his/her name there.
Similarly if you are using lotus script , you can give session.effectiveusername at that place. Pls check, I have not checked it practically, I may be wrong.
In your mail body Place a <computed value> and write the formula @name([cn];v3username) and teh complete you body , then send it , those who open get their own name
If you have a question how to put <computed value> in your mail body. Here is the answer
in you mail body put a cursor where you want to place the <computed value>, then go to menu “Create”>then select “Computed text”. You will find the <computed value>.
Now you put formula for this computed value.I hope you get this.