Before it
Instruction tuning needed human-written instruction-response pairs.
The problem
Writing tens of thousands of examples by hand is slow and expensive.
What it introduced
Bootstrap from a small seed set: have the model write new instructions and answers, filter, and train on the result.
Why it matters
It made instruction data nearly free, which is how small open models caught up so quickly in 2023.
What modern models inherit
Synthetic instruction data as a normal ingredient.
What came next
Alpaca applied it to GPT-3.5 outputs; the synthetic data line runs on to phi and beyond.