A twibbon is used to promote a cause on twitter by overlaying an image on your profile picture to show your allegiance to the twibbon cause.
A twibbon cause can be anything from a protest, memorial, event or even a popular person or band.
Twibbons can be created and supported on: twibbon.com
twibbon.com/join/RIP-Jackie-our-BH-sister to remember Jackie, a New Kids on the Block fan
twibbon.com/join/I-Love-McFly to support the band McFly
twibbon.com/join/WineBloggersConfrence to show you'll attend the Wine Bloggers' Conference