Kinda brilliant actually - convincing the AT&T guys of yore to give away everything for free so you can inject ads into a phone call. Yeah, that would certainly be met with disbelief, anyway I gotta go "skip some ads" on YouTube I'll talk to you later.
I do remember that. Little key fobs with one time codes. But that's still 3 years later. But apparently according to some of these comments large tech places were using 2FA in 2000 and as early as '98 or '99 which still surprises me, not really having seen it become ubiquitous until recently, and really only around things for banking and purchasing.