Americano vs.estadounidenses
There have been many threads regarding the correct term to use when speaking about ourselves as "American" in other countries. I finally remembered to ask my boyfriend to clarify. (He is from Mexico) He stated that neither term were correct. Americano refers to anyone living in the Americas and estadounidenses refers to Mexicans as well because their country is "Estados Unidos Mexicano". According to him, the term used exclusively for people from EE UU is "gringo" and that it does not refer to any other foreigner, but is exclusive to people who live in the United States of America.
I just thought I would share that bit of information with you-all. 
20 Answers
Most educated Mexicans think of themselves as Americans, as America is a very big place, much of which was Mexico in the Spanish time. It is just a matter of attidude, and not at all negative.
We, natives, speak Spanish here in the United States as well as many other languages. Foreigners that also speak our language but do not share our culture do not dictate how we perceive ourselves. I grew up understanding the name of my country is America and that I am an American in any language. Even if the United States were to fall the name of this land will still be America, any governments and constitutions to follow could not change that in my lifetime.
I say Soy Americano, if that offends you it's because you are ignorant. I am American American, you Argentinean American.
Additionally the Americas are two continents in spite of what you may recall from your dumbed down elementary school education ( BTW its supposed to be dumbed down you were eight years old). Consider is why Europe, Asia and Africa are not referred to as one continent, please use your critical reasoning skills.
I often say gringo, because that's what the majority of the people living in the places I travel use. I disagree that gringo is inherently negative or rude. It can be, but it's also used in a friendly way everywhere I've traveled in Central and South America.
If I meet someone on my travels who has what I think is an American accent, I very rarely think of the possibility that he may be Canadian. The two accents are very similar. So it is a forgiveable mistake to ask them if they are American.
A Scottish accent on the other had is so distinct than when you ask a Scorsman if he is English he gets very upset.
I have now learnt to "hear" a Canadian accent and when you say "you must be Canadian" the response is always a smile and, "how did you know?".
Have a look at this thread too,
