2345
2345 is a 5v5 arena composition consisting of the following classes and talent specializations:
This composition came to rise during Seasons 1 and 2, and remains extremely popular. It depends heavily on the Mage's "
[Shatter] Combo" (a 
[Frost Nova] followed by a 
[Frostbolt] and 
[Ice Lance]), and the Shaman's burst ability. The name is based on the joke that the Shaman must only hit 4 buttons -- 2,3,4, and 5-- to kill an opposing player. The corresponding abilities are 
[Heroism], a 
[Lightning Bolt], a 
[Ancestral Swiftness] instant 
[Chain Lightning], and a [Frost Shock]. This composition's weakness largely lies in the lack of crowd control abilities (only the Mage has a silence and a spammable crowd control) and lasting power, primarily due to a Mage's more limited mana pool and inability to drain or regenerate mana as quickly.
A popular variant of this composition called 2346 is run with a Siphon Life/Soul Link or Felguard Warlock instead of a Mage.
Later of in Wrath of the Lich King the composition of 2346 was run with a Destruction Warlock instead of a Mage.