Thank-You Notes - Emails Are A No-No

I'm a thank-you note kind of girl.  Not sure if it was my upbringing or just something I picked up along the way, but I think a nice hand written thank-you note after a meeting or an invite to a dinner, a gathering or a party at someone's home is always warranted.  I posted a while back about the lost art of handwriting so I know that an actual correspondence card, in an envelope, with a stamp on it thank-you note is seldom sent or received in this day and age of technology.  But what about for business?  What is the accepted norm when thanking someone for a business activity?  A presentation or symposium, a meeting, a lunch or a gathering? 
As an example, I attended a very interesting and valuable presentation last night about how to use a certain research tool that will be necessary and helpful in my future career.  I was incredibly impressed with the instructor who very patiently and thoroughly answered all questions, provided many useful examples and gave light anecdotes pertaining to the subject matter.  What is the proper way to thank her for her time?  I, of course, sent out a short email.  But the more I thought about it, the more I wondered if this was truly the acceptable way to show my appreciation.  To this end, I decided to consult my handy Business Etiquette - 101 Ways to Conduct Business with Charm and Savvy by Ann Marie Sabath and see what she had to say about the email thank-you note.  I was surprised that she absolutely does not approve of an email thank-you.  She firmly states that it is never acceptable, even in a business setting.  She asserts that "while it is true that any time someone exerts more than 15 minutes of energy to do something for you, a written or keyed thank you is definitely in order, but a thank-you note via email is like trying to give someone a hug without touching them."  By the way, the term keyed should obviously not be mistaken for email.  She means that while a hand written note is best (see? practice your handwriting!), one on the computer and sent via post is acceptable.  Interesting.  Her reasoning is that you want to show that you went out of your way to express your thanks and that you are not simply crossing off an item on your daily to-do list.  Absolute surprise on my part.  I was in breach of good and proper business etiquette.  Who knew?  With this in mind, I will certainly be more aware of the proper business "thank you" etiquette in the future and make sure I stock up on those beautiful embossed correspondence cards.   Of course, I hate to say it but I am sure that I will still be in the minority when it comes to proper business thank-you note etiquette.  Perhaps a little crash course for teens, along with manners and civility might not be a bad idea.