This is the Asexuality Flag.
The need for a flag was driven primarily by the desire to have a symbol that belongs to all of us, something that we could use to identify as ace and represent asexuality with that was not tied to a specific group. Prior to its adoption, people would use things like the AVEN triangle or a half-filled heart, but those had problems which prevented their wider adoption. The AVEN triangle is, well, the AVEN triangle. It’s the logo of a single website that not every asexual person is affiliated with. The half-filled heart implies romance, which meant that many aromantics were uncomfortable using it.
In the Summer of 2010, a number of asexuality sites, led by users on AVEN, came up with a number of designs for an asexuality flag, then held a multi-stage vote to determine the winner.
The selected design was created by AVEN user standup, and first posted at 4:36 PM on June 30th, 2010.
Some of the other designs included hearts and spades and triangles and all manner of other symbols. Some of the designs looked like country flags. In the end, the simple, four-bar design was chosen. This design avoids the unwanted connotations that specific symbols like a triangle or heart might have, it avoids any hint of national affiliation, and perhaps most importantly, it fits in with the striped designs of most other GSM pride flags.
(Plus, it’s really easy to draw.)
Since the flag was selected in 2010, its use has exploded. You can get buttons and bumper stickers and clothes with the flag on it. It’s been seen at pride parades around the world, and some flag makers now offer it for sale. Many asexuality related websites or blogs now incorporate the flag into their design. And, of course, people have even made ace flag cakes. Additionally, the black-grey-white-purple color scheme has been adopted by many aces as a way of indicating their asexuality. I’ve seen ace shirts, ace nail polish, ace friendship bracelets, ace headbands, and ace scarves. Even the logo of this site incorporates these four colors.
For more information:
You can trace the progression of designs and the voting process through these threads over at AVEN:
Here’s some shots of the flag in the wild: