Again, the general rule is that businesses that depend on so-called discretionary spending are in danger during economic downturns. The packed airports this summer might make this hard to believe, but jobs related to air travel, such as those in flight services and travel agencies, are at significant risk going forward. So are jobs in amusement parks, gambling, entertainment and tourism, where consumers can opt to cut back on their spending.

Construction work is notorious for its boom-bust cycles. And it's not just those working for homebuilders and realtors that suffer during housing downturns. So too, do workers in furniture and lighting, as well as household appliance and consumer electronics industries.

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Particularly susceptible to recessionary downdrafts are manufacturing jobs, especially those with capital goods manufacturers, like industrial and heavy machinery producers, as well as jobs with suppliers that are forced to bear the brunt of demand shifts at the consumer level. Especially vulnerable are auto and auto parts makers, along with makers of communication equipment like modems and switches, and electronic components like displays and integrated circuits, including very early inputs like semiconductor chips.