First time I heard this

Wage inertia was thus a blessing--albeit a poorly-understood blessing--rather than a curse. I think that everybody open-minded and nuanced is finding themselves moving rapidly toward the old Keynesian position under the pressure of events and data right now. DeLong

So Keynesians do not believe in market prices for labor. That explains a lot, they are price controllers!

I noticed that Kevin Drum didn't get the Delong Memo as he posts:

The problem is that we've gone through a financial collapse, households are overleveraged, and this has cratered demand for goods and services. With demand low, firms have no expectation that their business is likely to expand, so they aren't hiring unemployed workers at any wage. Add to that the social issues I mentioned above, and the long-term unemployed are screwed.

It seems to me that employers are doing what Delong wants, keeping wages high and employment down.
Yglesias has a better take, wages aren't sticky, it just takes time for economies to regain their footing:

But the basic relationship between the “people buying stuff” curve and the “people getting hired” curve is very normal. What is there that needs explaining?

Tyler Cowen started the issue, or rather Krugman started it with an attack on Casey Mulligan who uses microdata on employment. Kling has a good reply.

The stimulators should figure this out amongst themselves, and then try to convince the middle class to take on debt.

But I think Delong has the answer, wages are sticky because Keynesians in politics use regulation and controls to keep wages high and employment down. And we will see the Delong effect when his University loses $600M as Brown prefers sticky union wages to higher employment.