update readme with usage caveats and calls for research

This write-up was loosely inspired in part by Mitchell et al.’s work on
[Model Cards for Model Reporting](https://arxiv.org/abs/1810.03993).
Adding such model usage sections could be good practice in general for
open source research projects with potentially broad applications.

README.md

@@ -6,6 +6,22 @@ For now, we have only released a smaller (117M parameter) version of GPT-2.
 
 See more details in our [blog post](https://blog.openai.com/better-language-models/).
 
+## Usage
+
+This repository is meant to be a starting point for researchers and engineers to experiment with GPT-2-117M.  While GPT-2-117M is less proficient than GPT-2-1.5B, it is useful for a wide range of research and applications which could also apply to larger models.
+
+### Some caveats
+
+- GPT-2-117M robustness and worst case behaviors are not well-understood.  As with any machine-learned model, carefully evaluate GPT-2-117M for your use case, especially if used without fine-tuning or in safety-critical applications where reliability is important.
+- The dataset our GPT-2-117M was trained on contains many texts with [biases](https://twitter.com/TomerUllman/status/1101485289720242177) and factual inaccuracies, and thus GPT-2-117M is likely to be biased and inaccurate as well.
+- To avoid having samples mistaken as human-written, we recommend clearly labeling samples as synthetic before wide dissemination.  Our models are often incoherent or inaccurate in subtle ways, which takes more than a quick read for a human to notice.
+
+### Work with us
+
+Please [let us know](mailto:languagequestions@openai.com) if you’re doing interesting research with or working on applications of GPT-2-117M!  We’re especially interested in hearing from and potentially working with those who are studying
+- Potential malicious use cases and defenses against them (e.g. the detectability of synthetic text)
+- The extent of problematic content (e.g. bias) being baked into the models and effective mitigations
+
 ## Installation
 
 Git clone this repository, and `cd` into directory for remaining commands
@@ -53,7 +69,7 @@ and a valid install of [nvidia-docker 2.0](https://github.com/nvidia/nvidia-dock
 docker run --runtime=nvidia -it gpt-2 bash
 ```
 
-## Usage
+## Sampling scripts
 
 | WARNING: Samples are unfiltered and may contain offensive content. |
 | --- |
@@ -120,4 +136,4 @@ We are still considering release of the larger models.
 
 ## License
 
-MIT
+[MIT](./LICENSE)