A duckface is a certain expression
A duckface is something of this generation: young people with a smartphone who take a picture of themselves in the mirror. It is a pose where you make your lips very forward. When you make a picture of yourself, you are very much on a duck. Spouting your lips should make you look sexy, however this is usually not case. Often it's just a pout, and it usually looks the opposite of sexy out, but on MySpace (here it's started in 2006) and Facebook chokes on this profile pictures.
Images of Duckfaces