Every social security number possibly leaked in data breach

Discussion (91 points, 6 days ago, 83 comments) https://news.ycombinator.com/item?id=41184420

What could have people been doing to take more precautions when the breach was

"stolen personal records of 2.9 billion people from National Public Data, which offers personal information to employers, private investigators, staffing agencies and others doing background checks."