Not sure if you'll be interested, given there are juicier bits at the official site anyway (which seems to be offline now that I'm writing), but here's a little from the interview at Gaming Vision:

Gaming Vision:How important will factions play a role in character development as opposed to the previous games? Would I have to accomplish some goals in order to get accepted into certain factions like murdering random people to get into the famed Dark Brotherhood?

Bethesda: Certain guilds have requirements other than simply signing up to join. Joining the Dark Brotherhood requires that your character engage in some actions that might be deemed less-than-moral by any law enforcement characters in the area, and the only way to join the Thieves Guild is to let them come to you. You have to figure out a way to let them know you’re interested, though.

Looks quite nice... I like the factions in Morrowind but they seem to be a tad bit too uniform in their ranks and quests. Okay, the programmer in me smiles at the sight of a nice algorithm at work, and such a universal one as that, but if one could liven up the maths... I would appreciate that. ;)

I've heard the fighters and thieves guild are going to be in the game, as well as the Dark Brotherhood. But I would still love to see the Imperial Legion in. Maybe something to make up for the lack of houses? As in, perhaps, more guilds, or some political parties? Mercantile guilds wouldn't be bad. Or an imperial diplomatic service (think the Speechcraft skill). Or the Blades.

Oh, but here's the link:

http://www.gamingvisionnetwork.blogspot.com/

One of the things I disliked about Morrowind was how unrealistic the guilds were. You could get promoted for doing such insignificant things. An example was in the Balmora mages: find two papers in the same building you get the quest from, and you can be promoted. Meanwhile, the quest-giver has to research the alchemical uses of various flowers and fungi. Another is answering three riddles as part of the Imperial Legion. But from what I've seen and read in Oblivion previews, the guilds are going to be more fun.

The only guilds in Oblivion will be fighters, wizards, thieves, arena and Dark Brotherhood, though, as far as I know. I'm hoping they'll have a lot of depth to make up for the small number.

Oh yes, or the infamous West of Dagon Fel quests from the fighters guild and the Legion. Both seem to send you on easy quests after difficult quests. Perhaps it's realistic for you to get more lucrative contracts with a better cash per bruise ratio when you have moved up the ladder, or be hired by the princes of this world to solve their stupid problems only after you're important enough in the guild, but still.