Scan Oreo's Facebook posts, and something quickly becomes clear. Every post is about Oreo. They may not all feature specific products, but they all tie in to the brand somehow.

According to Facebook's own researchers, that's the most effective way to engage with fans on the site.

"The topicality of page posts impacts all types of engagement," says Elisabeth Diana, corporate communications manager at Facebook. "Speaking in the voice of the brand, talking directly about your product or service, or a topic related to the brand, is the best way to engage with fans of your page."

That seems to run counter to at least some notions of the best practices for brands on Facebook. For instance, an InformationWeek article from December warns, "Be sure to avoid over-focusing on your brand; fans know who you are already."

A recent Facebook study of hundreds of posts among more than 20 brands found that fans tend not to respond to posts that aren't about the brand.

Key findings

For the study, Facebook's research team divided brand posts into three buckets: posts strictly about products and services, posts related to the brand but not about specific products, and those completely unrelated to the brand.

You can find examples of all three at TGI Friday's Facebook page. A poll about the chain's new pretzels fits into bucket one, a question about a late night out fits in bucket two (Friday's brand evokes the weekend after all), and a joke about the Mayan end of the world goes into bucket three.

That last example from Friday's actually got a good many "likes," but it's the exception, Diana says.

"The bottom-line result is that posts related to the brand and the posts related to a product or service are the ones that are significant predictors of actions," she says. "The third, unrelated, is not a significantly predictive page post."

That means a post on your Facebook page that isn't about your brand is the only type of post that doesn't correlate with engagement.

What they mean

Diana says there's still plenty of research to be done on how brands should behave on Facebook to get the highest possible engagement.

"This is just the beginning of the research we're starting to do," she says.

Next, Facebook will probably look at how post frequency affects fan reaction.

"It may not be the nature of the message that people are sick of hearing," Diana says. "It may be it's too often."

As for the findings so far, Christine Campbell of Resolute Digital says they fit with her experience on Facebook. Most people are there to hang out with friends, she says. If they follow brands, they're probably looking for deals.

"It makes perfect sense that Levi's posts mentioning Levi's—new styles, discounts, etc.—would have a better engagement statistics than some obscure post only peripherally relating to Levi's," Campbell posits.

Shel Holtz of Holtz Communication + Technology points out that people "like" brands on Facebook because they're interested in the brand, not because they want to chat about their local sports team with them (unless the brand is related to that team). However, that doesn't mean brands shouldn't post about other topics.

"Being conversational makes the page more approachable," he says, "but it's mostly brand information that brand fans want."

Campbell says Facebook's research will probably affect how brands present themselves on Facebook, and that most brands don't really know what they're doing there anyway.

"It is important for brands to remember that especially now, as the online user is adapting and becoming both more aware and tolerant of brand presence in personal social online worlds," she says.

Other findings

A few other items in Facebook's research fit a little more snugly in the conventional wisdom.

The data show that people are most likely to share posts that include photos, photo albums or videos, Diana says. "The times I've actively wanted to share this with other people, it's always been a video," she adds.

To get "likes," ask for them.

"If you say, 'Like this if…' you're going to get likes," Diana offers. Those posts don't get shared or commented on very often, though.

If it's comments you want, ask a question. But Diana warns those posts are less likely to net likes or shares.

That all may seem like common sense, but Diana says "It's nice to have research to really show and illustrate this."

Matt Wilson is a staff writer for Ragan.com.

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