In case you've forgotten, it was Canadian Marshall McLuhan who coined the apt phrase, The medium is the message. He published the book with that title in 1967, or 1968, and it's still a valid statement.
What I want you to realize today is that you have so many media from which to choose to communicate your message: text, email, phone call, face-to-face meeting, teleseminar, book, blog post, billboard, messenger pigeon, etc. So, which one works the best?
Depends on your message. How important it is. Who is receiving this message. Budget and time constraints.
When in doubt, investigate your audience. See is she has any preferences. I know some people who almost always prefer to talk to you in person. And some prefer short messages through Twitter or Face book.
When in doubt, ask.
