Well, it's definitely much more common in Danish, but no - this has been when speaking (or typing) in English. My first introduction to USians was on a mailing list for L.M. Montgomery where a large part of the members were from Canada. You're right that they didn't want to be mistaken for people from the US, but the general consensus there, at the time, was that Americans was an expected way of referring to people living on the land masses between the Atlantic and the Pacific.
I actually haven't yet met any Canadians who spoke Danish.
I can only imagine they were pulling your leg because being Canadian, lived there most of my life there, met other Canadians while traveling around the world - I've never met a Canadian who called themselves American, except one instance where they were being deliberately messing with an American. I suspect they were, as they say "having a laugh".
I have personally only ever seen USian online.
I can assure you they weren't. It wasn't that type of conversation and it wasn't that type of mailing list. It was a small'ish mailing list, and we were friends rather than just "strangers who happened to meet online".
I have personally also only ever seen USian online. I doubt it'll ever make it to the spoken language.
Just talked with my Danish son. ( Exchange student from last year.) He said people from the US are Americans or Amerikaner. From other countries are referred to by their country, ie Kanadier. He said he might use Syd Amerikaner for someone from South America but that's about it.
Except for the last 4 words, I completely agree with him. People from the US may
be referred to as "Amerikanere" (but just as often "People from the US"), and to hopefully please the Canadians around, we'd never refer to Canadians alone as "Amerikanere". That would only be when talking more generally about people from the Americas. We might also split it up in "North American" and "South American".
He actually made me doubt myself though, so I went to look it up. This is from Gads lille lexicon for any Danes playing along. I hope you'll trust me that I've translated correctly.Amerika
combining name for the landmasses of the western hemisphere. Consists of two continents, North and South America. The term is sometimes also used about the USA. [Snipping the history]Amerikaner
a person from Amerika.
So basically we use "Amerika" to mean both "the Americas" and "America".
And thus ends your Danish lesson for today, I'm sure you were all just dying to know that
I'm sorry about the length.