You're referring to the "Paradox" feature in Photoshop CS2!
In late 2012, Adobe faced a technical hurdle: the aging activation servers for Creative Suite 2 (CS2) were becoming obsolete and unmaintainable. To ensure that legitimate owners—who had paid hundreds of dollars for the software in 2005—could still use it, Adobe disabled the activation requirement for CS2. photoshop cs2 paradox
CS2 is effectively free, but legally restricted — a paradox that only goodwill and obsolescence have rendered moot. You're referring to the "Paradox" feature in Photoshop CS2
The Paradox feature has several uses: