Stands for the Muffin Pie Man.
Someone who gave up everything to be with his APA and sworn to love and protect his APA forever.
Never fear, MPM is here.
Common typo for lol.
Most of the time it happens when you don't look at the keyboard or when you are typing really fast :p
Other common typos are kik and ;p;
person 1:HAHA lol
person 2:HAHA that's some funny shit mpm