Multiplayer

Multiplayer is a mode that allows you to play with more than one player in the game. There can be a maximum of eight players in a game. There are a many options for multiplayer:
 * LAN, which has been discontinued in Diablo III
 * Direct Connection through TCP/IP
 * Open and Closed Realms on Battle.net

Exploit in Diablo II: LoD
As of the 1.10 patch for Diablo II, it is possible to play the Single player-Mode in LoD in Multiplayer-Difficulty: Open the Chat-Box by pressing Enter. Type /players X, whereas X is a number from 1 to 8, in the Chat-Box. Acknowledge by pressing Enter and the message "players set to X" will display. Only newly spawned Monsters will be affected.

Disadvantages:
 * The minions of Hell grow in strength, receiving +50% maximum Life per 'player' above 1.
 * Boss Monsters have more special abilities.

Advantages:
 * Monsters deliver +50% EXP per 'player' above 1. This increase, however, is multiplied by EXP bonuses from equipment and shrines.
 * The probability for dropping items is increased.

This adjustment is dangerous for builds that rely heavily on Mana during the low character levels. On the other hand you can play on /players8 from the very beginning, if you are careful.

The drop probability is so high, that you will run out of space to store all the Chipped Gems and Runes before you can get the Horadric Cube.

The gained XP per Monster is so high, that it's easily possible to reach e.g. Level 12 before fighting Blood Raven, Level 20 before fighting Andariel and Level 45 before fighting Baal. (All of this with "/players8", still in Normal-Difficulty and without reruns.)

It is possible, though not recommended, to change back to "/players1" before a major Boss is spawned. Fighting him would be much easier, but he will drop less items and less valuable ones than you are used to.