In a move to prevent cheating, Blizzard has begun enforcing strict rules on players who abuse the Diablo II Battle.net servers. There has been an ongoing problem with a few players using hacks while playing Diablo II closed Battle.net games. In order to provide quality gameplay for everyone, players found using hacks will now find that their ability to join open games has been restricted.
This new measure will prevent players with a history of using hacks from joining open, non-passworded games on Battle.net. The only games these players will now be able to join will be games with other players identified using hack programs. This modification will affect all accounts associated with the CD-Key that has been identified utilizing hack programs. For more information on Diablo II, look into RPGamer's extensive game coverage.