Before it
Models trained at one context length degraded sharply when run on longer inputs.
The problem
Position embeddings do not generalise past the lengths they were trained on.
What it introduced
Drop position embeddings and instead subtract a penalty from attention scores proportional to distance.
Why it matters
It framed length extrapolation as a goal in itself and offered the main alternative to RoPE.
What modern models inherit
Length extrapolation as an explicit design criterion.
What came next
Used in BLOOM; RoPE with interpolation eventually won more adopters.