The game has more in common with a traditional RPG than an MMO
So said creative director Paul Sage whilst chatting with Gamespot at E3. He remarked that the game is designed more for RPG fans who want to experience the Elder Scrolls universe together than for hardcore MMO players.
You can wander around, explore and interact with things much as you did in Skyrim, and the game features a minimal HUD rather than reams of the busy-looking cooldown bars and tooltips typical of an MMO title. For the most part, rather than trying to cram the Elder Scrolls universe into an MMO format, developers Zenimax Online Studios has stuck with the winning Skyrim gameplay formula and adapted it up to suit multiple players adventuring together.
Therefore, there won't be raids. Or Auction Houses. Or end-game gear
According to an article on Just Push Start, The Elder Scrolls Online won't offer massive raid scenarios. There won't be gigantic bosses that require dozens of players to fell, but there will be instances that allow up to four players to explore together. Public dungeons will allow more than four players, of course, but they'll just be regular dungeons - so you may have to share the space with players outside your party. Which, as anyone with MMO experience will tell you, is a pain when there are large queues waiting to have their turn with enemy respawns.
The same JPS article also claims there won't be end-game gear grinding, so when you reach level 50, the best gear is obtained only through top-tier crafting. This doesn't sound very promising for end-game content, but developers insist that TESO will "most certainly" receive some expansions. A final blow for MMO-ers: there will be no Auction Houses. Players can trade with one another, but you'll have to find someone to trade with via the game's chat box rather than bartering in public.