"Yea" pronounced "yay" is a valid word with practically the same meaning as "yeah" (affirmative). Granted "yea" is archaic and most of the instances you are catching are just yeahs with the "h" dropped, but it would be nice to choose something that is definitively wrong. The anyway/anyways is a better choice and I hope that "anyways" does not become widely accepted because it is like Bieber to my ears.
I'm working on the assumption of statistical significance of people using "yea" pronounced "yeah" vs. the very few people who might have reason to take to Twitter to use "yea" in a voting or biblical context.
