[altintx]

NN were already a casual topic in my high school computer science class more than 20 years ago. I've always assumed they were already fairly common by that point. (~2000)

[Jensson]

They were a scientific curiosity at that point, the widespread use in the industry happened around 10-15 years ago.

[acdha]

They were known in the field but had a reputation for being too slow. I remember a couple of early 2000s NIPS (now NeurIPS) people commenting about what a shame it was that NN were computationally infeasible, which was true in the era before GPUs took off.

[kbelder]

They were and they were in use, for instance in character recognition. They just hadn't had their breakout success yet.

[Jensson]

Neural networks weren't the best models for character recognition, their breakout success was when they started being the best at recognize characters and other images which happened in the late 00's. OCR before then was really bad.

Might be hard to imagine today but back then OCR and image recognition was typically done with normal statistical regression models, and the neural networks they had then were worse than those.