According to TechCrunch, they are on track to do $5 MM in EBITDA, so they have about $15 MM in annual operating costs (before interest, tax, depreciation and amortization). This means that Dice paid about 4x operating profits.

Here's the link: http://techcrunch.com/2012/09/18/dice-holdings-buys-slashdot...

Presumably, that $20m/yr in revenue comes with a decent chunk of costs too.