There is a new AutoDesk blog about DWF from Scott Sheppard. He has an fairly nice overview of what a DWF is exactly and then goes on to explain why Adobe and AutoDesk are not 'at war' with their PDF and DWF standards. This is something I completely disagree with and I think subconsciously he does too with comments like "if you want to solve real problems... then PDF is not enough" and "never fly in a plane that was designed from a PDF".
A primary justification for DWF is the fact that it is intelligent and allows the capture of meta-data about a project for sharing. This is quite an ironic statement considering that that is exactly what a DWG and an IFC model do, the only difference is that for the time being DWF is firmly in the AutoDesk silo. DWF does have a lot more presentational characteristics compared to these two formats but the same effects are able to be generated using these formats without needing to create an entirely new proprietary standard.
AutoDesk and Adobe are fighting a battle within the collaboration space to establish a dominant standard for digital paper collaboration. It is a battle that at least in New Zealand Adobe is winning as most AEC professionals I have experience with exchange and accept PDF formatted documents whilst I know of only a couple that have experimented with DWF. Ultimately there will come a point where DWF will gain so many features that it will almost be impossible to distinguish it from its bigger brother DWG. When that time comes will we see a DWF Lite (or perhaps DWX as it sounds sexier).