Nudging, in this context, means social policy designed to encourage desirable behavior without restricting choice. A paper in the most recent Psychological Science looks at the effectiveness of nudging:
Governments are increasingly adopting behavioral science techniques for changing individual behavior in pursuit of policy objectives. The types of “nudge” interventions that governments are now adopting alter people’s decisions without coercion or significant changes to economic incentives. We calculated ratios of impact to cost for nudge interventions and for traditional policy tools, such as tax incentives and other financial inducements, and we found that nudge interventions often compare favorably with traditional interventions. We conclude that nudging is a valuable approach that should be used more often in conjunction with traditional policies, but more calculations are needed to determine the relative effectiveness of nudging.
Here is Cass Sunstein defends the idea of nudging:
And, of course:
peakmemory 
Another question is: how immune to bias are the people doing the nudging ?
As opposed to the people being nudged
So, to paraphrase Plato, “who will nudge the nudgers?”
Life is full of nudges and bias!! I must confess I often nudge my husband. The best nudge is the nudge where he thinks he came up with the desired behavior on his own!!! Please don’t give my secret away!!!