Consortium

Led by Nexus-Prince Haramad, the Consortium is a loosely affiliated cartel of ethereal smugglers, traders, and thieves that have come to Outland to benefit from its riches. Their main base of operations and biggest settlement is the Stormspire, but they can be found at Midrealm Post, Aeris Landing, within the Mana-Tombs of Auchindoun, and various other places.

They are also allied with another ethereal faction, the Protectorate.

Reputation
The general process for garnering reputation from the Consortium involves completing one-time quest chains which unlock repeatable quests. Some of these important quest chains are unlocked at specific reputation levels, which can make it somewhat confusing to follow. While it is possible to reach Exalted by using only Mana Tombs dungeon runs, that method is limited by the one-per-day heroic lockout.

Nagrand

 * 1) Visit a Consortium Recruiter in Nagrand and get The Consortium Needs You!.  This is only worth 10 reputation, but is not available if you've completed any other Consortium quests (such as the repeatable ones below).
 * 2) Go to Aeris Landing in Nagrand, accept both A Head Full of Ivory (3 Pair of Ivory Tusks) and Stealing from Thieves (10 Oshu'gun Crystal Fragment).  Pick one of these to complete, then complete the repeatable version of the one you picked until you reach friendly (12 total turnins including the first).  At that point, turn in the other quest—doing this will provide one additional turnin that would otherwise be unavailable later. The turn-in items are often found cheaply on the Auction House if you want to avoid farming.
 * 3) Complete the remaining quests at Aeris Landing.

Mana Tombs

 * 1) In Terokkar Forest, visit Eckert at Allerian Stronghold (Alliance: Eckert the Mad) or Grek at Stonebreaker Hold (Horde: Grek's Crazy Night).
 * 2) Take a normal dungeon run of Mana Tombs to complete all the dungeon quests and gain some reputation from mob kills.

Netherstorm

 * 1) At level 67+, complete all the available quests in provided by Consortium NPCs at Area 52, Midrealm Post, and Stormspire.
 * 2) At level 68+, complete all the Consortium quests at Tuluman's Landing and Protectorate Watch Post.
 * 3) Complete repeatable quests such as Another Heap of Ethereals as necessary to reach.

(Characters trying to simultaneously earn reputation with the Mag'har or Kurenai may want to focus on killing Ogres in Nagrand for Obsidian Warbeads to be turned in toward More Obsidian Warbeads Consortium turn-ins. Each ogre kill awards 10 Mag'har or Kurenai reputation. Doing this also nets many Oshu'gun Crystal Powder, for Halaa Research Token turnins, allowing a player to effectively farm their Nagrand faction rep, Consortium rep, and half of their Halaa tokens all at the same time.  The only caveat is the drop rate, which is roughly 33% for the warbeads, while it is 50% on the insignias.)

to (level 70+)
At level 70, return to Stormspire for Seek Out Ameer, then go to Protectorate Watch Post. Complete Commander Ameer's A Mission of Mercy there which allows Ethereum Prison Key to drop from enemy Ethereals and opens the Ethereum Secrets repeatable. The Keys can sometimes be found cheaply on the Auction Houses, and opening Ethereum Prisons can also net reputation from other Burning Crusade factions.

At Revered, Ameer's offers the A Thousand Worlds chain which leads to Bash'ir in Blade's Edge Mountains and opens another pair of repeatable reputation quests.

At this point, once all once-time quests have been completed, the fastest way to reach Exalted is via repeatable quests. Heroic Mana Tombs can also be cleared for reputation, but since it can be completed only once per day, you could choose to clear the trash only (avoiding bosses) and reset the instance.

The "daily dungeon" quests from Wind Trader Zhareem and Nether-Stalker Mah'duun in Lower City provide consortium rep, despite the NPCs not being marked as Consortium members (350 rep for Heroics, 250 for Non-Heroic).

Rewards
Upon reaching Friendly status, players are officially considered members of the Consortium and given a salary. The salary is a bag of gems at the beginning of every month, given by Gezhe at Aeris Landing. Higher reputation with the Consortium yields better and more jewels each month.

Mana-Tombs
Total Reputation Gained: 1,350
 * Undercutting the Competition (500 reputation)
 * Safety is Job One (350 reputation)
 * Someone Else's Hard Work Pays Off (500 reputation)

Nagrand
Total Reputation Gained: 2,010+
 * The Consortium Needs You! (+10 Reputation)
 * A Head Full of Ivory (+250 Reputation)
 * More Heads Full of Ivory (+250 Reputation) [Repeatable]
 * Stealing from Thieves (+250 Reputation)
 * More Crystal Fragments (+250 Reputation) [Repeatable]
 * Matters of Security (+250 Reputation)
 * Gava'xi (quest) (+250 Reputation)
 * Obsidian Warbeads (quest) (+250 Reputation)
 * More Obsidian Warbeads (+250 Reputation) [Repeatable]
 * Membership Benefits

Netherstorm
Total Reputation Gained: 1,360
 * The Flesh Lies... (250 Reputation)
 * Drijya Needs Your Help (10 reputation)
 * Sabotage the Warp-Gate! (350 reputation)
 * Arconus the Insatiable (quest) (250 reputation)
 * The Horrors of Pollution (250 reputation)
 * Escape from the Staging Grounds (250 reputation)

Tuluman's Landing
Total Reputation Gained: 500
 * Neutralizing the Nethermancers (250 reputation)
 * Dealing with the Foreman
 * Dealing with the Overmaster (250 reputation)

Stormspire
Total Reputation Gained: 1,850
 * Fel Reavers, No Thanks! (250 reputation)
 * The Best Defense (250 reputation)
 * Teleport This! (350 reputation)
 * In Search of Farahlite (250 reputation)
 * Hitting the Motherlode (250 reputation)
 * Surveying the Ruins (250 reputation)
 * The Minions of Culuthas (250 reputation)

Midrealm Post
Total Reputation Gained: 900
 * New Opportunities (250 reputation)

Protectorate Watch Post

 * Captain Tyralius (quest) (250 reputation)
 * Electro-Shock Goodness! (250 reputation)
 * A Not-So-Modest Proposal (250 reputation)

The Seek Out Ameer chain is long and rather convoluted, so a flowchart may be of use to make sense of it and its related keys and mobs.