I imagine most of you won't blink an eye if I tell you that Serena Software just laid off 10 percent of its 900-employee workforce. Layoffs have become a predictable, opportunistic excuse for poorly managed companies to conduct house-cleaning, a reflexive overreaction to turbulent markets which may well end up lengthening the recession. Serena Software is a software company whose software other software companies use to make software — right, exactly, the kind of boring company people do their best to ignore. Last year, CEO Jeremy Burton forced employees to spend an hour every Friday using Facebook. As late as June, the policy managed to garner press for the company from credulous hacks. But we think some of those employees now wish they'd ignored the Facebook diktat and spent Fridays working.