@trwnh yeah, they are, but the way they're used on twitter-like impls is to address people and target them directly, having mentions that to not "ping" is a secondary thing, so putting people mentioned in a post as CC seems wrong (e.g. why are you in cc for this reply, and not to? :blobcatupsidedown:)

soapbox (and apparently friendica?) does support pseudo-"arbitrary addressing" but soapbox still puts the mention tags anyway, not sure what friendica does because i haven't seen it in the wild

i think some zap software might also be able to do that but i haven't seen that either

pleroma has some C2S support, so you should be able to do that anyway but i haven't really tried