First, Barbie had Ken. Now, Barbie has a docking station.

A new doll hitting retail shelves this week is familiar in many ways — she’s got outfits galore — but she also has some unusual features: this Barbie, who is smaller and less shapely than her standard namesake, functions as an MP3 music player.

And when her feet are plugged into the iPodesque docking station that she comes with, she unlocks pages and pages of games, virtual shops and online chatting functions on the BarbieGirls.com Web site.

The new doll is a roundabout way of charging for online content. Instead of asking young Web surfers to punch in their parents’ credit card numbers, BarbieGirls.com and other sites are sending customers to a real-world toy store first. Some of these sites (like the Barbie one) can be used in a limited way without purchasing merchandise — the better to whet young appetites — but others, like the popular Webkinz site, are of little or no use without a store-bought product or two (or three, or a dozen).

The trends that have brought about BarbieGirls, Webkinz and their ilk are clear: While sales of dolls, action figures and outdoor toys are down, electronics sales to children were up 16.6 percent over the last two years as of May, the latest month available from the NPD Group, a research firm that tracks retail trends. The total toy industry’s annual sales were up just 0.8 percent in May, compared with two years ago.

With children’s leisure-time habits shifting online, toy companies are responding with new products that can be construed as fun both online and offline. That Barbie in the docking station? Go to a physical store and buy her an extra outfit, and you get access to even more Web content.

Products like these represent a change not only in the design and function of toys, but also in how toy makers use their Web properties. Mattel, for instance, like many consumer goods companies, has until now treated Barbie.com, HotWheels.com and its 22 or so other Web sites as advertising forums, places to showcase toys with the hope that children will nag their parents for them. But now Mattel and others are trying to turn their sites into money-makers in their own right. Although BarbieGirls toys are just now hitting the market, Mattel has paved the way for them: about 3 million people have registered since April 27 on the BarbieGirls Web site, a virtual world where playing games can earn a visitor play money — “B Bucks” — that can be spent on the likes of miniskirts, tiaras or home accessories. And, that’s without Mattel advertising the BarbieGirls site, even on its Barbie.com home page.

Mattel’s new toy follows the success of Webkinz, a line of Web-savvy stuffed animals made by Ganz, which also sells various sigh-inducing (albeit unplugged) teddy bears. Each Webkinz comes with a number code that, once entered online, starts an “adoption” process and ushers the owner into a virtual world that amounts to a Second Life for the grade-school set.

More such products are on the way. This month Zizzle, the company that makes Pirates of the Caribbean toys (not to mention Lucky the Incredible Wonder Pup, perhaps the first stuffed Labradoodle) is introducing an online/offline toy. SpotzGirl.com is a bubblegum-pink Web site with games (that people can play free) plus a collection of girly images (pussycats, hearts) that can be made into round physical tokens.

How does one make them? With the help of the Spotz Maker, a new-age button-maker that will be available in stores for $24.99. Girls will be able to create jewelry, decorate picture frames and collect and trade their Spotz, which are sort of like charm bracelet tokens.

“Over the next few years, you’ll see a lot of companies finding ways to create products that are Web enabled,” said, Marc Rosenberg, chief marketing officer at Zizzle. “The monetization for us comes from the product, and not from the Web.”

The concept behind Web-connected toys is not new. In the late 1990s, a number of toy companies introduced physical goods that could be used to unlock online goodies.

One noteworthy attempt came from The Learning Company, an educational software company that was owned for a short time by Mattel. But concepts like physical telescopes that could zoom to far-away islands when aimed at an Internet-connected computer failed to take off, in large part because Internet connections were too slow.

But times have changed tremendously. “Kids look at video content or virtual content as their toys,” said Jessi Dunne, executive vice president of global toys for Disney. “There isn’t a distinction between — ‘That’s a toy’ and ‘That’s an online game.’ ”

These days stores routinely sell out of the $10 to $13 Webkinz — pandas, lions, hippos and other animals that unlock the online fun on “Webkinz World.” There, on the site, customers can play with avatars of their pets, shop for them using “KinzCash,” decorate their pets’ rooms, enter online tournaments and chat with their real-world friends.

“The Webkinz concept is still doing very well,” said Robert A. Eckert, Mattel’s chief executive, in the company’s second-quarter earnings conference call. “That phenomenon is real, and will continue to do well.”

So real, indeed, that the starter set for the BarbieGirls site — sold for $59.99 — will be one of this holiday season’s main Barbie products. Mattel plans to run some television ads for the product in the fall, but the site is expected to be the primarily driver of sales, said Chuck Scothon, general manager and senior vice president of girls, Mattel Brands.

“For girls to understand the level of detail, the level of content, truly the experience of BarbieGirls,” Mr. Scothon said, “we wanted to allow them to play on the site.”

Toy companies also may benefit from the Web by using it to provide add-ons to products. Toy makers could sell cheaper products with a base-level of features, then allow customers to log online to choose what custom functions they want to download, said John Rose, a senior partner and managing director at the Boston Consulting Group and leader of the firm’s Global Convergence Initiative.

Even as toy companies cash in, some media executives are wondering if they, too, might use physical products to generate new revenue for their Web sites. Neopets.com, for instance, a virtual world of whimsical creatures and games, draws more than 10 million visitors a month, according to Viacom, which owns it, and although T-shirts and other Neopet-related merchandise is for sale, it is not the main draw.

MTV, a Viacom subsidiary, has started marketing toys that relate to its Web content. Earlier this month, the network introduced a music video game, “Rock Band,” in partnership with Electronic Arts. The game allows up to four people to play along with various songs using physical instruments hooked into an Xbox 360 or PlayStation 3.

“We’re looking at it as more of an add-on. Can we do something a little bit extra or a little bit different?” said Mika Salmi, president of global digital media at MTV Networks, which includes MTV, Nickeolodeon, VH1 and other networks. “The idea of connecting experiences is very, very important to us, but the absolute model is not established.”

The Walt Disney Company, too, has gotten into the act. Last year, it introduced a digital camera that lets people download images of Disney characters from its Web site to their photos. Disney will introduce an analogous video camera this fall and has other online/offline toys in development, said Ms. Dunne of Disney.

“I think Disney’s a perfect example of where it will work,” she said. “We have an advantage as a media company because we have all this, where toy companies have to create content. That’s not necessarily their sweet spot.”