Smartphones Susceptible to Smudge Hacking (PDF)
Don't get too paranoid about this, but security researchers at the University of Pennsylvania have shown than Android graphical passwords can be recovered by photographing the screen of a smartphone and analyzing the smudge patterns. There isn't much likelihood of this attack being used widely, because its utility requires either gaining control of the smartphone or the same password being used elsewhere, and the screen can easily be cleaned. But it's still interesting just where security vulnerabilities will be found.