The huge variety of games and activities is by far the site's best feature. Some are habit-forming and addictive, including math, word and shape puzzles in the vein of "Tetris" or sudoku. Most reward critical thinking in some fashion or another.

Some games appeal to the very young — my 3-year-old laughed uncontrollably at one game where you whack a puffball-type creature with a club — and others appeal to adults and teens. I suspect many players are adults, either using their children's accounts like we do or childless adults who have moved on from their Beanie Baby collections.

The games can be played solo or two-player, and the Web site will usually find you a challenger in seconds. You can see the site's appeal to adults late at night, when the arcade is still hopping and the level of competition on those word puzzle games rises dramatically.

Some of the games seem complicated even for older kids. A dice game that is apparently popular was a little confounding. Mark needs help playing some games, but can do others by himself. The variety is sufficient to please everybody.

The lack of advertising on the site is also welcome. The Web site provides rewards and incentives for buying additional toys but does not seem particularly aggressive in pushing kids to spend real money. Some features, like tending to a garden, reward players who log on to the site every day. My wife says it promotes responsibility, though I find it mildly obnoxious to insist on my child's daily participation.

The ability to outfit your pet's living quarters is also staggering. Thousands of virtual items are available for purchase, from custom towel racks for the bathroom, swimming pools for the backyard and designer clothes for your pet to wear.

The virtual shopping mimics real online shopping, with "add to cart" icons. Some may see it as indoctrination into real online shopping, but we were actually pleased because my son is learning to save money, forgoing smaller items to buy the big stuff.

And it provides an interesting window into what kids find appealing. I was a little surprised he spent so much time selecting particular types of furniture.

The Web site limits the ability to chat and interact with other users to a series of prefab questions and statements — "What's Up?" "I'm feeling tired." "Do you want to play in the arcade?" and so on. That makes it impossible for skeevy pervs to prey on children.

Unfortunately those limitations — while necessary — also make it difficult to have any substantive interaction. Playing a live opponent really feels no different from playing a computer. What's the fun of winning "Rock Paper Scissors" if you can't trash-talk your opponent after your rock whomps all over his scissors?

The interactions with your virtual pet are also a little stilted, and like politicians, the virtual pets have a tendency to pander to their audience.