Twitter formalizes blocking of accounts and tweets that encourage readers to follow you on other social media sites, including Mastodon.

Specific examples of violating tweets given in the policy:

> “follow me @username on Instagram”

> “[email protected]

https://help.twitter.com/en/rules-and-policies/social-platforms-policy

Promotion of Alternative Social Platforms Policy | Twitter Help

@Pwnallthethings @username

Musk: Twitter is the main driver of engagement and referrals on the internet

Also Musk: so we gonna suspend journalists and ban external referrals

@hu_logic @Pwnallthethings @username the advertisers must be really happy.
@mawhrin @Pwnallthethings @username I'm pretty sure click-through rates are already in the gutter. So, yeah, this is likely one of the final nails in the ad revenue coffin...