I am a native English speaker from England, but I've noticed that "Dear" has died out from emails and then letters. I am trying to write a semi-formal thank-you card, but I don't know whether to put "Dear" or "Hi". (Probably doesn't matter, but don't want to start by sounding weird!) In an email or a letter I'd put "Hi" to the recipient, but a card somehow seems more formal.
As far as I can tell from Google, it is only in America or in emails that people are getting in tizwoz about the connotations of "Dear"; discussions of any sort of letter on UK websites all have "Dear" as standard without questioning it. Is that correct?