That wasn’t terribly professional. A U.S. Department of Labor probe determined that the online career network violated wage law and must now cough up $6 million in back pay and damages for 359 workers. At issue? A failure to record and compensate for all hours worked, in violation of the Fair Labor Standards Act. LinkedIn said the violations were technical errors rather than law-dodging, but the firm has its work cut out for it in resolving the issue.