@thejonymyster it's uncountable, so you can't use it with "a", but you'd still say "this data is" (grammatically singular) instead of "these data are" (which is the old / "technically correct" version)
@Mayube right sorry that one was a joke, but i think if were going to have the word "datum" it cant be part of the same word as "data" anymore, "data" has moved on and become a strong independent uncountable
@thejonymyster it's not fighting a losing battle against change, because nothing's changing. data is the plural of datum. data is also an uncountable noun. Words can have multiple usages depending on context
@Mayube Personally I dislike "data" as a plural because it's inconsistent with "information", and I find the concept of a single datum kind of pointless