They refer to Sims 2 as a "den" in that you're only playing one house at a time, and everything in the rest of the neighborhood stays static. "... in The Sims 3, the den becomes a warren, and 'everything you would expect to be happening is happening, whatever the time of day.... All of the characters in the town are changing together. You can zoom in on your Sims. You can go next door to visit your neighbors. You can knock on the door or peek in the window. You can go downtown, and the people you meet are people in your Sims' lives. What would happen if you ran into your boss on the weekend in town? Would you ruin your Sim's life by doing something embarrassing?' That time-lost little boy next door from The Sims 2 now ages and changes alongside your own child. 'They can become high school sweethearts....they can grown up together, get married, have a family of their own -- and those characters will advance along with your family."

-- "The number of attribute bars has been reduced from eight to three, with one -- a "stress versus fun" meter -- standing out as the most essential. Sims still need to bathe, sleep, and eat, but the gauge presenting liters of urine versus free bladder space is hidden behind the curtain. 'We've added one-off mechanics like the buffs in World of Warcraft... In our case, if [your Sim's] out in the rain, he would have a debuff -- we call them moodlets -- that would just say that he's soaked now and he's miserable. Or if his mom dies, he'll get a moodlet that makes him miserable. It'll go away after a certain amount of time, or you can get rid of it. IF there's a way to get rid of it.' Moodlets range from simple things like "I'm thirsty!" with immediate psychological effects to "I just got a promotion!" that can grant a boost that carries for days."

-- you can "tidy up the hamster cage." Basically, you have a Hand of God now, so if your sim leaves trash around, you can clean it up, or if they leave a book out, you can put it back on the bookshelf instead of directing them to do it.

-- your sims can actually be fat now (and they actually look fat instead of not-quite-skinny). "In The Sims 3, you'll now be able to use a slider to adjust your Sims' body weight over a much broader spectrum, from relatively obese to skeletally thin and everywhere in between. You'll also be able to use a separate slider to adjust musculature -- separate from body weight -- allowing for a huge amount of variation: fat dude with spaghetti arms, skinny dude with big guns -- basically, any body type you can think of. And that body type won't remain static depending on how you play the game."

--"'... one Sim might go to the beach, come home, and paint one version of a sunset. And if you bring another Sim to the beach, he'll paint a different version of that exact same sunset.' So while the base images are the same, different Sims might have an Impressionist take, Dadist, postmodernist, or realist, determined by a set of algorithmic genes."

-- They're trying to add a lot of random parameters to the game to make Sims unique. "Each Sim has a favorite coffee drink... but every Sim in the world has a different drink.....It's mostly for flavor, but the devil is in the details. 'We want the Sim to feel like unique snowflakes in The Sims 3,' says Humble, 'and less like the only difference is their clothes and their hair. If you don't want to get to know him -- if you just want him to pee himself -- well, that's fine, because you can still do that."

-- No personality sliders, instead there's a system of 80 or so Traits you use to establish their identity. "You can pick up to five Traits for each Sim, only some of which are mutually exclusive (for example, you can't be both "good" and "evil"), to create an almost endless variety of personalities. Some Traits are behavioral, such as "inappropriate," which might cause your Sim to interact rudely with other Sims, while others are more strategic gameplay modifiers, like "genius," which would let you gain any intellectual skill, like reading books, faster."

"-- One single, set map of Pleasant Valley is all that ships with The Sims 3, partially because randomly generated towns simply wouldn't jell artistically, and partially because even though The Sims is a single-player game, history's shown that its player base wants to share." They go on to talk about how everybody had a Goopy in their neighborhood and there was a sense of community formed from everyone talking to each other about how he acted/what they did with him in their game.

-- "...all of the buildings in Pleasant Valley...are places you can visit and interact with. Exactly what that interaction will be depends on the situation, but in a nutshell, the designers have broken locations up into two broad categories. There are 'rabbit holes,' the informal in-house term for a building your Sim will disappear into without you actually following inside (for example, you won't follow your Sim into his office job and watch him space out on the Web for eight hours), and there are venues, which are locations such as a pool or park, that will be filled with lots of Sims and accoutrements of all types to interact with."

-- "... your Sim will now walk out of your home and see and visit other Sims, other buildings, and other neighborhoods in real time. The world is changing and evolving around you, characters are going on with their lives, marrying, aging, and dying, as you proceed with your own life. And every action you take may have a ripple effect that spreads across the town and affects the lives of multiple generations."

-- Dreams and Promises: "Your Sim might walk past a cute Sims on the street and think, 'I'd like to get to know her better.' And you can Promise that you're going to make that happen.... Anything can trigger a Dream at any time, and a new Dream is represented by a thought balloon over your Sim's portrait. Buy your child a telescope and he may Dream of being an astronaut after a few nights of stargazing. Promise to make his Dream come true -- even if you can't until the day before he dies -- and he'll gain a significant mood boost. A Dream might also be as simple as wanting to buy a book -- inspired by walking past the bookstore downtown, learning how to cook, or simply sitting idly on the couch with nothing better to do..... Unfulfilled Dreams aren't penalized; they're just forgotten until another one comes along. Broken Promises, however, make for melancholy Sims -- like a Sims 2 Fear realized, only players get to determine whether to be afraid in the first place. The philosophy is opt-in gameplay. The Sims 3's attempt to make itself if not everything to everyone, then at least as much as possible to as many as it can. The creative types can forget the Promises entirely and major in movie-making and fashion design; those in it for the "game" can choose to challenge themselves as they see fit."

-- "Where in the Sims 2, Sims would vanish to work for a set amount of time .... Sims 3 allows players to customize what they do while in the office -- even if the game doesn't go so far as to let you control them as they chop broccoli or process purchase orders. (Work is still mainly off-limits, for reasons as simple as it would be a crushing bore.) .... 'You can decide if you want to leave early or stay late -- if you want to take it easy or suck up to your boss,' effectively sleeping your way to the top.... 'of course, if your boss dies, or gets married to someone else, you're kinda screwed.'"

-- "Careers also form the base for another new Sims 3 system called Opportunities, the functional equivalent of MMORPG quests -- only instead of fetching 15 landshark fins, you're planting 15 tomatoes or shacking up with 15 women."

-- Social interactions allow you to change the tone of a conversation, so being best friends doesn't automatically mean you're going to be flirting with them "Here, you actually make the conscious choice of pursuing a romantic relationship..."

-- "We're going to be releasing world-building tools," says Bell, "advanced tools definitely for the modding community. On TheSims3.com, there'll be an exchange where you can download towns from other players.".... Godat hints at how the exchange might operate: "People put hundreds of thousands of Half-Life maps out on the internet. The Web has a way of giving them a star rating, and people go and download the five-star maps-- it's the same kind of thing here. We know that people are gonna go and build new versions of our buildings. We can elevate these things through our connection to the community--find some way to tell a player that, 'Yes, this building slows your game down.' Find some other way to let them find the content that they're really excited about and tell that story they want to tell. That's what keeps it going for so many years.'"