A huge concern that no one seems to be mentioning is that pretty much all academic data sets that used the Twitter API were required by the TOS to only be released publicly with the tweet ids, not the content of the tweet. Some of these have hundreds of thousands of tweets, and the only way to check the work of the researchers, or to build on it, is to use the api to reseed everything yourself.

With this new policy that practically becomes impossible (the costs would be outrageous for a researcher, much less an individual).

This will have the effect of essentially destroying 15 years worth of social science work that was based on Twitter data, it's all gone.

If you're a researcher who has published a data set with only IDs but have a private version with all tweet data I highly encourage you to publish that internal dataset. I'm putting together some hosting for anyone that needs it, feel free to get in touch and we can take it from there.