A place devoted to high-pressure telephonic promotion of stocks/bonds/commodities/contracts/etc (which are of very questionable value). Extensive fraud is usually involved. However, successful prosecution may be difficult, because operations often disband before detection; and since little tangible evidence is obtainable.
Congratulations! You're now Froogled Up™ on what "Boiler Room" means!
Feel free to use it throughout your financial/insurance life.
