> We recognize that many of our users are active on other social media platforms. However, we will no longer allow free promotion of certain social media platforms on Twitter.
> Specifically, we will remove accounts created solely for the purpose of promoting other social platforms and content that contains links or usernames for the following platforms: Facebook, Instagram, Mastodon, Truth Social, Tribel, Nostr and Post.
And from Elon Musk:
> Casually sharing occasional links is fine, but no more relentless advertising of competitors for free, which is absurd in the extreme.