Matthew Graybosch is a user on octodon.social. You can follow them or interact with them if you have an account anywhere in the fediverse.
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Cross-posting is marketing for the source platform, so you shouldn't be surprised I don't think Twitter to Mastodon cross-posting is beneficial to Mastodon.
Mastodon is a social network, and talking to each other is a big part of it. If someone has setup a cross-poster and left and never checks their notifications, it's pointless for us who are here.
@gargron Can you block cross-posters without breaking OStatus or ActivityPub?
@starbreaker @Gargron many twitter clients added features to mute via source (e.g. via "Facebook" or "YouTube" or "Twitter for Android" or whatever)