No response from my friend. Why?

Hmm. Here in the US it is expected to send thank you notes for all gifts.. Some people do not, but most do. Also, I could understand her being too busey for the note, but to ignore the e mail worries me. Have you tried calling her telephone at home? I would try that next. I too do not like that feeling. Wondering what you might have done to offend someone? I would try to call and then maybe send another e mail. Also, do you have other friends that keep in touch with her. Maybe have them try to contact her.