There is *no* "interoperability" between #Mastodon and #Threads currently
You can search for "Threads.net" and find profiles (Mosseri et al) than can seem to be opened on Mastodon, but they are *not* linked back to the original profiles on Threads
Thus you can *seem* to reply to one of those profiles on Mastodon, but your reply does *not* propagate back to the original profile on Threads
@mosseri -- seeming to be here on Mastodon -- is an illusion
FYI: wordpress.com (hosted) sites have the ActivityPub bridge built in. Self hosted WordPress sites have it available through a plug-in: https://wordpress.org/plugins/activitypub/
@mastodonmigration All good points. One quibble: I wouldn't say that the ActivityPub plugin for WordPress is a "bridge". We usually use that term when there are two networks joined together. WordPress is a native, integrated part of the fediverse.