Filesharing will always evolve. What is killing the porn industry isn't that the file-serv/Tube sites/torrents exist, but that their legit, for pay sites continue to offer poorer selection, lesser convenience, lesser quality than the illegit ones at frankly absurd prices.

Example:
http://www.adultdvdempire.com/1602229/nothing-but-sexxx-vol-2-porn-videos.html
Windows only download for $25. Streaming one week rental for $17 Beyond a joke.
Yes, not everyone is this bad, but they are a typical example.

Until there is a iTunes for porn that sells all content from all companies at $1 a pop DRM free H.264, in HD where applicable, the "piracy" problem will only get worse.

Keep in mind that Megaupload was gone after because they were hosting MPAA controlled Hollywood movies and RIAA controlled music, not porn. The feds wouldn't be reaching all the way to New Zealand for some porn only site.

The whack a mole game has never worked. Only a legit alternative that is better and more convenient than the free version will ever work.