This was an extremely difficult question to find an answer to, but I managed to settle on "factions." I took this to mean guilds, however. At any rate, I settled on this because the lack of meaningful or fulfilling guild quests in Skyrim is perhaps the single-most disheartening feature of the game for me. There's just so much untapped potential (Oblivion guilds were far more fleshed out and meaningful) that I was very disappointed with the guilds I've completed and cannot bring myself to touch the others; I've heard horror stories about the College.
Flesh out the guilds, Mr. Todd. You owe us that much.
Yes the College quest line was a let down... Don't get me wrong it was still fun, and there were some cool set pieces. I just expected a lot more. Magic in general is kind of a let down in Skyrim though. Sure we got dual casting, but we lost quite a bit too! Like:
No spell creation :banghead:
No "Drain" spells :verymad:
No "Night-Eye" spell :nope:
No "Ease Burden" spells :banghead:
No skill fortification spells :verymad:
No health, stamina, or magicka fortification spells :verymad:
No "Open Lock" spell :banghead:
No bound armor (although I would just use Ebonyflesh anyway, still looked cool though) :mellow:
Only three bound weapons :verymad:
Only five summoned creatures :banghead:
Need I go on?
In all honesty, I feel that players who like to create Mage type characters got overlooked in the making of Skyrim. That's why I REALLY REALLY hope they get the hook-up in future DLC... Psijic Order anyone?