mpft is a very versatile word... it can be used to express emotion. Can be used as an adjective (just like smurf). You can use it when you don't know what to say, even if the occasion is sad (at least you said something). If the words are failing you while writing a card/letter/mail you can substitute mpft for truck-loads of sentences... at least you wrote something, right?
If you are in chat, you can let people know that you are indeed awake and just lurking by typing the occasional mpft.
What is life without mpft? Surely can't be worth listening
What in mpft world are you mpfting?
Writing to wish you happy mpfting.
I am a pround mpfter