It's not on this site, and seems to rarely be used as a name. It's an epithet of Athena.
Personally, I love it. I gave it to a game character that I play a lot and it's really, really, really grown on me... but I've also notice a lot of variation in how people pronounce it. Personally, I say "i-tohn-ya", but I've heard "i-tohn-ee-ah" and "ee-tahn-ya" and all variation in between!
What do you guys think? Do you think it's viable to use in real life? How would you pronounce it?