There is a growing tendency for people to send cards reflecting a donation to some charitable institution -- not even necessarily for matanot l'evyonim -- in lieu of giving mishlo'ach manot. This, to me, somewhat misses the point. Not to say that tzedakah is not a significant mitzvah but Torah is far from monolithic and each mitzvah has its own significance. There is a reason behind mishlo'ach manot and its significance may be becoming lost.
I wrote more on this in my latest Tribune article at
Rabbi Ben Hecht