It’s not an official sequel or a new site. Typically, names like this refer to community-run proxy or mirror sites—unofficial copies of the original TPB index. The “4” might indicate a version number, a specific proxy list entry, or simply a way to avoid domain seizures.
However, if you are looking for a about the phenomenon of Pirate Bay mirrors (like the concept of “piratebay4”), here is a draft you could use for a tech or digital-rights focused blog or forum: Title: What is “PirateBay4”? The Cat-and-Mouse Game of Torrent Mirrors piratebay4
What’s your take? Have you seen a “PirateBay4” domain pop up lately, or is this just another ghost in the machine? It’s not an official sequel or a new site
So, what exactly is “PirateBay4”?