Lemonade is a fizzy drink, strongly carbonated. It comes in two varieties, white (which is actually colourless) and red. I have never known anyone to make it at home.
Various things I've picked up in reading suggest that all three of the above sentences are untrue in American English, and the second sentence is untrue anywhere outside of Ireland.
Best Answer
Lemonade is not necessarily carbonated in Ireland. You can get the nice stuff here too. It's also not like we don't know how to mix lemon juice and sugar-water (protip: add one lime's juice and a sprig of mint), and haven't been doing so for centuries.
Conversely, the Americans have the fizzy stuff too.
Pink lemonade (both fizzy and non-fizzy) is found all over the world too. The brand I've seen most often in Ireland is French.
I agree that the deep red stuff seems to be much more common in Ireland than anywhere else, though its rarer here than it used to be. I haven't seen the brown variety in a long time, though I think C&C might still make it. I understand they were originally developed to be used as mixers with red ale (for a shandy) and whiskey respectively, so it may have been changes in tastes for alcoholic drinks that led to brown lemonade being rarer now.
In all, the word covers the fizzy and non-fizzy varieties of various different colours all over the world, but differences in preferences for the drink itself affect what will first come to mind when you hear it spoken.