I have heard many MMOs offer very similar things. I don't mean to disrespect ZOS, but content every 4-6 weeks is impossible. Unless they just rework dungeons a bit and call that new content, i don't see how they can put out quality tested content that often. Square Enix made a similar claim for FFXIV:ARR and the first update was almost 4 weeks late. PC will get the updates sooner than Xbox One and PS4 though, since Sony and Microsoft will need to do their weekly stalling for any update on their systems.

Sony does a pretty good job with EQ2 about providing new content ona pretty consistant basis, new dungeons and overland raid zones etc every few months. It all comes down to how streamline their pipeline is, how much of a plug and play type system they have (think creation kit) and how much of the new content will need new (models, music, lighting, and scripting etc). I would expect large( new zones, storylines, AV zones) content to take 3-6 months but adding new public dungeons and smaller quest chains etc to be feesable in a 4-6 week time period, even if that is just to the PTS and not to the live server.

Most developers that I've seen that have missed the mark were reeling in game fixes and dealing with client issues well after launch. So I guess this promise highly depends on how well the current state of the game is finished & polished.

Rift did the same at the start.

Want to be added?

Dungeons, guilds, raid like stuff, housing.

I doubt ZOS has specific new content rollouts on a fixed schedule, probably target dates. They have an idea how fast players will consume content but ESO is a new game so their estimates will turn out to be too optimistic..

ZOS's first tripwire will be on April 30-May 1. That's when they get their first indication of how good the game really is. The 30-day free period will be runing out and anyone who wants to continue playing will have to start thinking about the $15 which will be showing up on their credit card statement. Why April 30-May 1? If the fanbois and enthusiasts don't start signing up by then, that will be a huge red flag and it'll be panic time at ZOS. So if they reveal or bring out the 'big guns' like Dark Brotherhood or Thieve's Guild early...

But if the early access players are still spending crazy amounts of time in-game and start paying monthly subs, ZOS has the luxury of parceling out new content at a more deliberate pace.

Almost certain they'll fall behind on their first update. Slowed down by launch issues, refining their battle plan against RMTs/botters/hackers, etc. After that, well we'll see.