"Although the interactive documentary -- or iDoc -- is maturing, the field (and the terminology) remains subject to definition. (The MIT Open Documentary Lab's exhaustive "docubase" shows the variation over the years.) "Delivery platforms -- whether TV or film -- used to dictate the length and format of a documentary," says Ingrid Kopp, director of digital initiatives at New York's Tribeca Film Festival. "Now nothing is formalised, because the web isn't -- it doesn't dictate those structures. Everything is now wide open."