I guess it's just a natural progression with regard to technology, enabling people to take advantage of new tools as they become available.
It's much simpler to type a few words, or even a whole page, than it is to prepare a card or missive and travel to somewhere few are likely to read what has been written.
The message still conveys the same meaning, but there's less effort required in the delivery and the potential audience is greater.
E-mail seemed a little odd in it's infancy, but the majority are sending them these days and the delivery is almost instant.
An old friend of mine took his own life a few years ago, following a period of depression and family issues.
He was a people person and one of the toughest, but fairest doormen you would ever want to meet.
His funeral service was packed full and there were probably three or four times as many people outside, as there were inside, listening to the service via hastily-rigged speakers.
The page, set up in his memory upon his passing, is still active and I 'talk' to him every now and then, along with countless others.