Joblessness In America: A Stickier Problem

The article suggested a possible problem faced by the economy with respect to the unemployment issue: high unemployment now comprises of a higher portion of 'structural unemployment' such that stimulus could not alone be the cure.

Reading through the lines of the article, I found several questions that are open for discussions:

1. Why is it that after a number of stimuli, fiscally or monetarily, the recovery is still slow and unemployment rate is still high. If this is the 'lag' for the stimuli to take effects, how long would such 'lag' be - or how much more stimuli should we employ in order to cope with our problem of unemployment? Otherwise, is the question whether such stimuli are not effective in this situation valid?

2. One main point from the article is about the reduced efficiency of the Labor Market that is followed by the housing and financial bust and, recently, is exacerbated by the reduced incentives to seek for job thanks to better unemployment benefits, raising the 'natural' unemployment rate of the US.

First of all, what effects are left after the housing and financial bust that makes people less likely to be employed, increasing the 'structural' unemployment rate? Another question that comes up along this line is that: how would a "more determined effort to help those trapped in "negative equity" to restructure the mortgages on their homes" work out? (one of the strategy suggested by the article to add to the list of things combating unemployment)

Second, taking for granted that the article is right about making labor market more efficient by creating incentives to seek for jobs, how could such "overhaul scheme" be designed?