yeah in America if you call another man "mate" it will sound like he is your boyfriend haha. "Man" is commonly used but mostly between friends....I wouldn't call someone I had just met "man".

If you're asking that the words are interchangeable, then no. I often get Americans gleefully telling me that 'mate'='sexual partner', though such a meaning isn't commonly recognised in UK/Australia. To us, it roughly means 'friend'. In Australia, we do pepper "mate" all through our speech similar to how Americans use "man". It can be quite funny how often we use "mate"! In this usage, the word kind-of functions as a sentence marker, tucked between phrases. It still includes the listener in the story and holds onto their attention. It's also probably more a habit than anything else, so if you were planning to use "man/mate" in speech, you need to listen to a lot of native speakers first to get an idea of how often and when to use it. Surprisingly, this habit also happens in a lot of the ancient Greek texts - phrases such as "man, be happy!" and "man, I understand what you're saying" often turn up in translation. So the habit is by no means new in language.

I disagree with Marie-Helene. Americans say man as in, "C'mon, man!" "Ah, man!" "Let's go man" "Hey man, whatcha doin?" But Brits say "Hey mate" "My mate & I were at the local pub..." In the last example, you cannot substitute 'mate' with 'man' unless you want to symbolize that's your boyfriend. Mate is used in British English as another word for (usually guy) friend. It seems like a more chummy way to greet your friends and to refer to them. In American English, man is commonly used as part of an exasperated expression, like being frustrated or out of patience or upset. It doesn't necessarily refer only to someone of the male gender. Americans also sometimes substitute "dude," another slang term not necessarily referring to a specific male but in the general exclamatory sense. As Marie-Helene mentions, saying man (or dude) may in fact be a bad habit of America's youth. For the British, though, mate does not fall into that same category.

Hi... yes it is the same bad habit... lol!