Americana is a name made up by hatcheries after the Ameracauna breed standard was accepted. Their flocks that were previously under that name no longer fit that standard so they shouldn't be using it. Easter Egger is another name made up hatcheries, it's a very marketable name.
From my point of view, I think Americana would be used more for EEs that have that traditional look of muffs and beards. (Though I really don't like the use of the name as it's misleading.) These days you can get more EEs from mixes of other blue egg layers so they can have vastly different looks, but should still have the chance of laying a blue or green egg. For example, I previously hatched eggs from my brown layer hens sired by my Crested Cream Legbar rooster (blue egg only breed). I called them EEs because the female offspring would lay green eggs. However, Americana and EE are not names for a specific breed with a set standard, so really there's no set definition on when to use the names.
