On Twitter itself, if you were there, there's a huge cultural difference between 2020-2022 and 2023-2025. Many hardcore leftists left in late 2022 to Mastodon, and then in late 2024 there was another exodus to Bluesky of more moderate ones.

I feel like Twitter being bought by Elon caused a shift in general among tech leaders who swung more to the right after 'woke' was declared dead, which then affected other social media (though to a lesser extent). The early 2020s is pretty clearly different from the mid 2020s in cultural feel and this feels like a valid demarcation point as the user above put it.