What does Identity Theft Monitoring Flag?

[Anonymous]

My info was stolen through filing out info for a clearance (as was my DHs).

I signed up for the Identity Theft Monitoring Service. Recently I opened a new credit card as refinanced my HELOC with a different bank.

I was surprised that neither of these items flagged anything and my report came across as "None of your personal information was detected last month through the Identity Theft Monitoring service". In contrast, my husband who was on the HELOC did receive a report through the same service that his ID was used.

Does anyone know how these services work?