I write proper letters in my email, when I have enough to say.

I've read stories taking place at the turn of the century where characters wrote enormous letters about everything, as if they were diary entries meant for an audience. They were written in a casual voice, similar to the voice the character would use on the phone if he had one (of course, real dialogue is always more broken up than letters). And there was always something to say, because the character was committed to maintaining a relationship with the audience.