There are reports in this Flyertalk thread that getting bumped on Delta flights now comes with an increased incentive.
In the past Delta provided the following
Up to 3.5 Hour Delay = $200 Delta Dollars
Over 3.5 Hour Delay = $400 Delta Dollars
The Reported New Levels
Domestic – Either $400 or $600 Delta Dollars regardless of time frame.
International – The level has been raised to $600 to $750 Delta Dollars
In the past a less than 3.5 hour delay meant you would earn a rate of about $57 Delta Dollars per hour for your time. Going forward if you can earn $400 Delta Dollars for a 2 hour delay this would bring your rate to about $200 per hour for your time. In my opinion this is time well spent. We will have a first hand report soon. If you have any experiences with the new Voluntary Denied Boarding levels, please post an update in our comments.