It turns out there’s some truth to the common Twitter put-down: A lot of people go online to talk about the sandwich they just ate. But they’re not just talking about it, they’re photographing it.

Why? In many cases, people are documenting their lives — or at least the gustatory portion of it. There are other reasons, too. Sometimes, it’s to celebrate the completion of a dish or a special occasion. Some folks are photographing "food art."

At least once a month, 52% of people take photos with their mobile phones; another 19% upload those photos to the web. There's enough of that group practicing "foodtography" to support the website Foodspotting, as well as a 2,500-member Foodtography group on Flickr. Photoblogging apps like Instagram and the latest, photo-enabled version of Foursquare are likely to further fuel the trend.

Reasoning that marketers should pay more attention to such nonverbal web communication, interactive agency 360i recently did a deep dive into the data and found a few constants. One: People are almost never in the pictures; only 10% of hundreds of photos that 360i analyzed for this infographic included human beings. Two: It's rare to see any brand mention — that happened just 12% of the time.

So what are we to take away from this? The agency isn’t completely sure, but according to a blog entry posted Monday, it sees a huge opportunity for brands. If you’re a marketer who’s hungry for new insights, this might be a good place to dig in.

Image courtesy of Flickr, Lara604