Psychology of "Thank You" letters

[K.I.L.E.R]

I was in a business meeting and my mentor mentioned that we should send a hand written letter of thanks to the women who set up the YAA workshop.
Anyway I asked "Why?" and he mentioned that it makes people feel good when you send a 'Thank You' letter to someone that's written by hand and not by e-mail.

We discussed why this is good but I still don't understand the point.
Even if it makes the person have better personal relations with you, what's the point of that?
I'm not sure if this requires a psychology doctorine to understand but can someone please explain this to me?
Thanks.

 

[Fodder]

It's a who you know, not what you know world.

 

[arjan de lumens]

Networking effects. If you're being perceived as an asshole, the person perceiving you as the asshole is likely to spread that perception on to other people; this in turn is likely to make people unfriendly towards you, sometimes even people who do not have an obvious direct connection to the one you were being an asshole against. This in turn makes it harder to get people to do what you want them to do.

 

[Diplo]

It's very simple. A handwritten letter shows that more effort and attention has been made thus showing the person that your business treats them as a valued customer/associate. If they feel valued then they are more likely to do business with you thus enhancing the chances of making a profit.

 

[LunchBox]

handwritten letters have a more personal touch than let's say an email with...

Dear (insert name here)
Thank you for buying (insert product here)