It can sometimes denote a transfer of interest from the writer's business to the reader's. It can be a way to denigrate oneself in deference to the more-important reader.
Or it can simply a way to write-off what one just said or wrote. It can be a way to make light of the subject at hand and change the subject with humor of a somewhat-undefinable word.
It can be spoken as "Any who" or "Any whoooooo ... "
It spins from the Yoo-hoo fruit drink/chocolate milk slogan, "Wherever your action is."