The biggest brand on Google+ isn't Coca-Cola or Disney or Starbucks, the top three on Facebook. It isn't even Google itself. Since Google opened up its social media platform to brands in November, the company that most users have added to their circles—530,000 and counting—is Swedish clothing chain H&M.

"At Google+ we have chosen to focus on inspiration," says Jennifer Ward, a spokeswoman for the company. "Nice images, films, and, of course, a lot of fashion."

Ward says H&M doesn't discuss the specifics of its social media strategies. However, Jonathan Rick, director at Levick Strategic Communications, says he sees what they're doing.

"H&M's approach to Google+ is spot-on: lots of pics of people sporting H&M clothes, together with a quick caption. Even better, H&M includes a link to buy the given clothing."

Rick and other experts picked up some other key elements to H&M's strategy on Google+, and laid out how Google's platform differs from Facebook.

Post photos, and often

Nearly every post on H&M's Google+ page includes a photo or video. For a fashion brand, that's a no-brainer, Rick says.

"H&M is selling clothing, which in ads means a lifestyle. The way to market this is not through words but through visuals."

For other brands, visuals may not be quite as important, he says. "The model depends on the brand. While visuals are always important, words—explanatory text—can be just as crucial."

Rick notes that H&M posts to Google+ quite frequently. For instance, the company posted more than two dozen photos to the site Monday, along with a few other updates.

"Ordinarily, I'd advise against this inundatory approach, but it's hard to argue with H&M's success," he says.

According to Ward, "We think it is important to be active and post news every day, just as in our other social media channels, and we are also careful to make sure that what we publish is relevant to our followers."

Christine Campbell, program manager for SEO and social media at Resolute Digital, says H&M knows its audience of shoppers looking for affordable, "indie" fashions and who often come to stores looking for new items.

"The content (on H&M's Google+ page) is relatively 'indie,' and by extension, trendy, featuring artistic, aesthetically pleasing photos and videos filled with indie celebrity names like Sofia Coppola, Drew Barrymore, Milla Jovovich, Rose McGowan, Shirley Manson, Lykke Li, Freida Pinto, Mena Suvari, Anton Yelchin, Rashida Jones and David Beckham," she points out.

Campbell also notes that H&M frequently posts about contests on its Google+ page.

"This is a tried-and-true-strategy from Facebook brand marketing that traditionally works well."

Exclusivity

H&M constantly tells its Google+ following that the content is "exclusive" and they're getting a "first look" at a new collection.

"We want our followers on Google+ to feel that what they get is unique compared to what that get by visiting for example hm.com, Facebook or Twitter," Ward says.

That's important, Campbell says. The page "replicates not only the experience of shopping in the store, on the website or via the catalog, but also cultivates the feeling of exclusivity for people who interact with and embody the brand by supplying a constant stream of interactive content tailored specifically to the G+ following."

Google+ vs. Facebook

H&M is king of the mountain on Google+, but Google's network is little more than a big hill in comparison to Facebook's Everest, Rick says. H&M itself has 20 times more fans on Facebook, he notes.

Still, Rick says brands should experiment with Google's social media platform. Getting in at the still-ground level will allow you to embrace the spaghetti approach," he says. "Whatever sticks to the wall."

Some brands have tried to differentiate their Google+ pages from their Facebook pages through posting longer messages, says Joe Ciarallo of Buddy Media.

"Obviously that is different than Twitter, and slightly different than Facebook, where brands are either forced to, or choose to post short content because it sees higher engagement," he says.

For Campbell, the big difference between Google+ and Facebook is all in the "circles" function.

"With this key tool, marketers get user interaction results in real-time," she says. "No longer is there a need for private messaging or multiple email campaigns—content is both readily available within the network and targeted to different groups, all under the control of the account administrators."

Campbell points out that H&M has blocked users from seeing who it's added to its own circles. That may be a smart move, she says.

"I am safely betting that there are dedicated circles for each different type of user, from brand novices—people unfamiliar with H&M¡to brand advocators—people who promote H&M within their personal social networks."

Matt Wilson is a staff writer for Ragan.com.