No quotation marks.
I've been reading a few Nobel Prize laureates recently. Cramming your poor dialogue into giant undifferentiated paragraphs seems to do the trick.
In all seriousness, it is an interesting technique. I'm not suggesting that anyone take it as far as Saramago, but give it a try. There is a curious immediacy to it. You forget you're reading a novel. It feels like a close record of events as they happen(ed).
The book I'm writing now might be fantasy, or might fit in mainstream literature. I'll experiment with yanking out the quotation marks and see what happens.
Oslo, here I come.