Once, people looking at porn on their computer kept a quickly clickable screen image on hand -- say, a letter to their mother -- should someone enter the room.

Now, Mom may be the one looking at porn sites: food porn, or shoe porn, or cabin porn, or garden porn. Seriously. Consider bookshelfporn, a photoblog of impressive bookcases from around the world. Or chartporn.org, described as "an addictive collection of beautiful charts, graphs, maps and interactive data visualizations."

Because images on porn sites are meant to entice and arouse, it's little wonder that the word has been co-opted by folks who obsess about more mundane aspects of life.

Amanda Simpson, founder of a popular food site, was one of the early co-opters. In 2008, she bought the domain name www.foodporndaily.com and began posting larger-than-life photos of dishes such as the bacon-wrapped chicken legs featured last Tuesday that make Kim Kardashian's video career pale in comparison. Within the first 24 hours, they had more than 100,000 page views.

Today, among the 7 billion results in a Google search for sites in which "porn" is preceded by a word, FoodPornDaily is No. 3.

"I find that cooks who take food seriously always refer to how sexy the food on the plate is," said Simpson, 31, "so it's easy to see how sexy food talk can lead to the term 'food porn.'"

Simpson's site grew from a desire to feature better food photography than the usual thumbnail shots. In other words, size mattered. As she explained: "Food porn is a high-resolution, up-close image of food that tricks your brain into thinking that it's actually in front of you, induces drooling and makes you hit the fridge to devour whatever you have available."

Social taboos always entice

The word "porn" comes from the ancient Greek word for harlot, or prostitute, but the pruning of the word "pornography" to porn didn't occur consistently until the 1960s. Thank you, Hugh Hefner.

We're talking about taboo behavior, said Blake Howald, a computational linguist for Ultralingua, a Minneapolis company that makes language software and maintains dictionaries for our rapidly expanding language. He's also a linguist at the University of Minnesota.

Think about the behavior associated with pornography, Howald said: "You hide it, it comes in a brown paper bag, it is sinful, and you have to keep it a secret." Yet when the word is applied to gorgeous gardens, "it has nothing to do with behavior of prostitutes or lewd sexual acts, but rather what people's [assumed] behavior is in relation to porn."

Howald said the process happens with other taboo words, "like being a 'shoe whore.' The semantic process of going from something specific to something general over time is not an unusual process," he said. Think of Kleenex referred to all facial tissues. "But the types of reactions you get with the 'porn' examples have to do with social perceptions of taboo."

In other words, porn has a "made you look" power and a cultural edginess. Thus, associating something as ordinary as charts to porn can lead to more page views, as well as a perception of pushing the envelope of social acceptance -- sometimes known as being "cool."

Naughty, or offensive?

Simpson said she didn't realize that the term "food porn" would generate such interest, "but I think we all like to be a little naughty without actually being so. Sex, in our culture, is seen as taboo, so to have a site that refers to porn, but actually has nothing to do with sex, pushes the ticket."

Still, there's some social awkwardness in telling a friend about a website featuring cabins and chalets from around the world, only to hear:

Cool, what's it called?

Uh, freecabinporn.com.

Silence.

Seriously?

Donna Dunn, executive director of the Minnesota Coalition Against Sexual Assault in St. Paul, had a similar response.

"Why would anyone think that pornography sets a standard of beauty that applies not only to women, but to gardens and food?" she asked. "We need to change the culture in which we raise our boys and girls because it's sexually toxic, and this is a really good example."

She already can imagine some people's response: "Oh, it's just a joke. Don't you have a sense of humor?"

"We're not talking about porn," she said, "but the fact is that the more this happens, the more it hijacks our thinking about who sets the standards of beauty and expression in our culture. Ultimately, it starts normalizing the environment where porn is a positive adjective to use."

She urges people to become more "media-literate" -- to appreciate the power of language, "and then to say, 'Let's not go there.'"

Time is money; so are clicks

Amid the talk of taboos and sinfulness, the ultimate vice of clicking through image after image of stunning stilettos is, mostly, wasting time.

Simpson said it appears that her main demographic is college kids killing time in class. But it's not just students, given that FoodPornDaily has had almost 75 million page views.

Yet the life of a food pornographer, as Simpson calls herself, is not all whipped cream. "I'm actually pretty frequently concerned about whether or not my e-mails go through since lots of them contain the word porn," she said.

Worse, when she released the FoodPornDaily cookbook in 2010, "I couldn't get distribution in Williams Sonoma or Sur la Table simply for the fact that the book's title contained the word 'porn,'" she said. She's moved on. As, she says, has the country.

"Whether or not all generations of the American public are ready to start referring to things outside of just sex as porn, the movement is happening. It's just natural for language to evolve alongside culture."