Not exactly. The version of vBulletin this site uses is listed as a version of 3 but it's a hybrid, a corporate version for the sites owned by the company which owns this site and several others and has no relation to the original;vB3 nor is it 4. No reversion was done, the platform was developed specifically for those sites.
Our owner also owns vBulletin Solutions.
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I don't know nothing, and I memorized it in school and got this here paper I'm proud of to show it.