What does DDF stand for?

What does DDF mean?

DDF	Drug and Disease Free Internet » Chat
DDF	Dynamic Depth Focusing Miscellaneous » Photography
DDF	Doctor's Dermatologic Formula Business » Products
DDF	Dangerous Drunk Family Community
DDF	Darkness Distortion Factor Miscellaneous » Photography
DDF	Dubai Duty Free Business » International Business
DDF	Dublin Dance Festival Community » Performing Arts
DDF	Defect and Diffusion Forum Internet
DDF	Drop Dead Fred Community » Media
DDF	Deutsche Diversified Trust mrger DRT Business » ASX Symbols
DDF	drug and disease free Medical