I sent my thank you also by e-mail today and no matter what you may think a thank you is always appreciated and noticed whether it's a corporation or a single individual and it never hurts to express your appreciation. Business are made up of people just like you and me and they like to know the public appreciates what they are doing. My company is not huge but it's large in our community and when someone sends a complimentary e-mail it is forwarded to all the employees so it is not "stupid" to send a thank you note. It is a smart thing to do.