Twitter will not allow free promotion of certain social media platforms
This is stunning.  What is a violation of this policy?

  At both the Tweet level and the account level, we will remove any free promotion of prohibited 3rd-party social media platforms, such as linking out (i.e. using URLs) to any of the below platforms on Twitter, or providing your handle without a URL:

  Prohibited platforms:

  - Facebook, Instagram, Mastodon, Truth Social, Tribel, Post and Nostr
  - 3rd-party social media link aggregators such as linktr.ee, lnk.bio
  - Examples:
    - “follow me @username on Instagram”
    - “username@mastodon.social”
    - “check out my profile on Facebook - facebook.com/username”

(https://help.twitter.com/en/rules-and-policies/social-platfo...)