taken from the reference to MacDaddy, which he isn't. MattDaddy is a blogger who talks about his kids, being a father/husband, technical stuff, and the Boston Redsox
A MattDaddy is someone who is devoted to his family, a good father, and a good enough husband for the wife to tolerate his sorry stinkin butt.
A mandaddy is someone who is that dude. He's smooth with the ladies and everybody loves him. He turns up whenever he can and he is always the life of the party. Girls want to be with him and guys wanna be him.