Seth Godin made this interesting post the other day:

"One by one, traditions that supported technology are falling as the technology changes. The simple thank you note, for example, is a long tradition based on the technology of couriers and then the postal service. Of course it arrives three days later, because that's how long it takes. At first, the email thank you note seems too impersonal, too easy, too digital. Then, we begin to appreciate the speed and it become ubiquitous and then expected."

Sounds like an opportunity!  In the land of the blind...

I'm working at thank you notes - I traveled to one of our locations and was sitting at the desk of one of my directs.  Glanced at the cube wall - you can learn a lot about a person from their walls - and there, tacked on the wall was one of my thank you notes.  I also noticed that there weren't any emails tacked up there.