

That’s a fairly recent feature to let the instance admin curate the popular and all feeds. I.e. not show posts from specific instances and(?) not on the front page. It’s in the announcement of PieFed v1.6.23 here: https://piefed.social/c/piefed_meta/p/2048738/piefed-v1-6-23-is-released
Instance silencing similar to Mastodon. A silenced instance is not defederated from but their posts do not show in the Popular or All feeds and their communities are not shown in Starter packs aka Topics. Their communities can still be found in the communities list and joined in the normal way. Once joined, posts in there show up in the subscribed feed as usual.



Depends. Those are just letters. First and foremost meant to scare you and do something without thinking it through. You can decide to respond, or not respond, that’s up to you. Though it’s strongly recommended to contact a lawyer before signing any contract with them, admitting to wrongdoing or give them information about yourself. I’d probably try to avoid (5) without legal advise.
If you toss it in the bin, they’ll have to decide whether they have enough evidence and whether it’s worth the effort to actually sue you. Usually that letter was an invitation to settle out of court. At their terms and conditions, though.
And yes, they’re most certainly backed by the media companies. Otherwise they wouldn’t have any business messing with their intellectual property. And maybe the law firm only does letters, maybe they have some number of court cases to achieve each month, who knows? Maybe they already exhausted their more promising X court cases this month and you won’t hear from them again if you decide to just ignore them. Maybe you’re one of the “lucky” few who get sued.