The author, founder of the V-Club in NYC, writes:
"Is there a sudden mass feminist amnesia about the difference between a vagina and a vulva?" my dear friend Emily Kofron pondered. "I doubt that men would tolerate a supposed celebration of their sexuality that confused a scrotum or testicle with a penis. Are we women so accustomed to subordination that we remain pathetically grateful for any acknowledgement of our female genitalia no matter how inaccurate?"
The difference between the vagina and the vulva probably doesn't seem like an issue worth discussing to most people. But when you look at it in a larger context, it's hard to believe that raising "vulva consciousness," as the author calls it, isn't part of our (at least not mine) typical feminist discourse.
I encourage you to read the article. I, for one, will make a conscious effort to use these terms correctly from now on, not interchangeably.