* Trump has been bannned from Twitter.
* Trump has attempted to use the POTUS account, and had those tweets removed.
* Trump has been removed from Facebook.
* Trump has been banned from Twitch.
* The Discord server for the_donald has been banned from Discord.
* Parler has been removed from the Google Play Store and the App Store.
* AWS has announced plans to discontinue Parler's hosting.
And I think that's about it, for very recently. For those who support Trump, "deplatforming" is a major concern, as Trump has now lost access to essentially all of his base via social media. Once he's out of office, he's not going to have anywhere near as significant a reach as he may have.