I'm not a Rep nor a Dev but I am a Dav n' I can Rap (not really) but here is some old and newish info on Companies.
http://forum.square-enix.com/ffxiv/t...l=1#post141384
Company SystemIntroduction of the Grand Companies
-NEW-
Implementation of command centers in the three city-states
-NEW-
Appearance of the three commanders
-NEW-
Implementation of a contribution system and rewards
-NEW-
Ongoing addition of rewards and expansion of content
-NEW-
Grand Companies quests
-NEW-
Development of the Grand Companies for the three city-states and design of accompanying questsIntroduction of additional quests
http://forum.square-enix.com/ffxiv/t...l=1#post127940
http://forum.square-enix.com/ffxiv/t...l=1#post128011
http://forum.square-enix.com/ffxiv/t...ll=1#post85828
The Grand Companies will do the nations of Limsa Lominsa, Gridania, and Ul’dah justice as their stalwart representatives, and related content such as quests will begin to go live in patch 1.17. We’ll also be seeing the rulers of each of the companies come forth. A historic set of events is primed to take place in Eorzea, so be sure to keep a sharp eye out!
http://forum.square-enix.com/ffxiv/t...l=1#post101658
http://forum.square-enix.com/ffxiv/t...l=1#post117475
Instanced dungeons will provide a means to further solidify the bonds of the Maelstrom, the Immortal Flames, and the Order of the Twin Adder. The Grand Companies are large-scale organizations that will play an active role in the events going on in Eorzea as they happen, so be on the lookout!
Somewhere there is a Letter or Dev Post that says Jobs will likely be unlocked thru Company Quests but I couldn't find it.