"Starting today [September 25, 2007], the Isohunt team will deny access to all US visitors on their TorrentBox and Podtropolis tracker. They are forced to take this action because of their involvement in a lawsuit initiated by the MPAA."
IsoHunt crew statement:
As of earlier today, we have disabled access from users in the US to our trackers. This goes for ALL trackers (torrentbox, podtropolis) we run. This is due to the US’s hostility towards P2P technologies, and we feel with our current lawsuit brought by the MPAA, we can no longer ensure your security and privacy in the US. So, if you’re outside the US, you may notice less peers. We encourage you to add other public, unhampered trackers to torrents you post, in addition to Torrentbox and Podtropolis’s trackers. Source: TorrentFreak