Michelle Hainer

When Rachel Sarah of Oakland, Calif., first heard about Club Penguin, a social networking site for kids, she had no idea what it was.

"My daughter kept asking me if she could use it," recalls Sarah. Not sure whether her daughter, who's under 13, was too young to be on the Web, Sarah decided to check it out herself. "There aren't any ads, and the site seems really fun and innocent," says Sarah.

But how can you be sure a site is really what it seems?

We’ve done the legwork for you and found the top three social networks for kids. Here’s how they keep kids entertained while making their safety a top priority:

CLUB PENGUIN

Kids are given a penguin avatar that can interact with the other penguins on the site, play games and earn coins to buy accessories for their penguin or furniture for their igloo. Membership is $5.95 per month for premium access, which allows kids to customize their penguins.

Age group

8 to 14, although older kids can join too. Parents register kids who are under 13.

What kids love

The penguins are simple and cute. Kids can get creative when customizing the look of their penguin and igloo, and meet other penguin friends for coffee or tea.

Privacy and safety features

Parents can choose between the Standard Safe-Chat, which allows kids to type their own chat messages, or Ultimate Safe-Chat, which restricts them to prewritten words or phrases, like "Hello" or "What's up?" "Club Penguin has really strong filters, so you won't need to worry about kids swearing or going crazy," says Anastasia Goodstein, author of Totally Wired: What Teens and Tweens Are Really Doing Online.

WEBKINZ

To enter the Webkinz world, you need to buy an actual Webkinz stuffed animal. (Store info is available on the website; teddy retails for around $14.) Each animal comes with a code that grants access to the site.

Age group

6 to 13, although adults can log on too.

What kids love

Their stuffed animals come alive online. Kids can buy food for their pet, decorate its room and win KinzCash by playing arcade games.

Privacy and safety features

Parents can choose KinzChat Plus, where users are restricted to words or phrases listed in the site's dictionary. Children must have their parents consent to access this area. (Kids need to provide their parents’ email address and must wait for their parents to reply to Webkinz's request before they’re let in.) Check out the Parents area

WHYVILLE

After creating their avatar, kids can travel through Whyville's beaches, boutiques and clubs, chatting with friends.

Age group

Although the site's cartoon design mainly attracts kids, anyone can register at Whyville. In compliance with the Children's Online Privacy Protection Act (COPPA), children under 13 are required to get their parents’ permission before signing up. (This is true for any website that solicits personally identifiable information from kids.)

What kids love

Whyville users can earn "clams," the site's currency, by starting their own business, playing games or accomplishing tasks (like sorting food or recycling in the cafeteria). "Whyville is great for kids with imagination," says Goodstein.

Privacy and safety features

Whyville offers what it dubs “communications tools,” which it says helps increase safety. For example, if a user is behaving badly, kids can create a 911 report about them. Individuals called City Workers also police the site -- though not 24/7 -- to make sure no one's getting out of line.

No matter which site you pick, be sure to read the privacy policy, parents’ section (if they offer one) and keep tabs on your child’s usage. Sarah, for one, limits her daughter's Club Penguin use to a couple of hours a week, but overall she's happy to have found a website that's both fun and educational. "My daughter is improving her math skills because she's learning to save money to buy things and she's typing notes to the other penguins," she says. Plus, she's developing her online skills in a safe way.