Need a little motivation to lose those nagging 10 pounds? Or seal the big deal? Or book that beach vacation?

Aherk! suggests putting your online rep, well, on the line.

The beta website with the goofy name amps up the pressure by asking users to post a goal and deadline. But it doesn't stop there.

The user also e-mails Aherk! an embarrassing photo - referred to as "the bomb" on the site. When the deadline hits, Facebook friends vote on whether the goal was achieved. If not, up goes that incriminating pic at the expense of some social media status. Of course, if those 10 pounds really came off, all's well in the World Wide Web.

The power of negative reinforcement seems to have its fans. Besides Aherk!, other penalty-focused platforms include the GymPact, where missed workouts (tracked via smartphone) cost greenbacks, and Write or Die, a harsh cure for writer's block. If you sit idle too long at your laptop, your work - the very words you've struggled to put down - start to unwrite themselves.

And let's not forget diet program MetaReal's Virtual Fridge Lock - a new device that attaches to the refrigerator, senses when the door of said refrigerator is opened, and shames the midnight snacker by posting to his or her Facebook timeline: "This person just raided the fridge."

Certainly, when people tweet on Twitter, update job histories on LinkedIn, or post their status on Facebook, they are careful to construct an online personality of which they're proud. Being shamed in front of the world (literally) puts that curated identity at risk - a surefire motivator for any savvy networker.

"Essentially, these new services almost blackmail people," says Margot Mason, a trend analyst with the Intelligence Group, based in New York, who recently noted the phenomenon in "Cassandra Daily," an e-mail publication of the Intelligence Group that identifies pop culture trends. "This is a desperate measure, compromising your social media identity."

Aherk!, founded by a Brazilian entrepreneur, has more than 250 goals listed on its site. Many sound like typical, often failed New Year's resolutions: lose weight, find a job, quit smoking. Other popular goals include saving money, spending more time at home, traveling to a beach, and learning to play a musical instrument.

"Have the guts?" challenges Aherk!

Lia Marques, 35, did. The Sao Paulo, Brazil, transplant to Los Angeles helped test the site. Her goal?

"It wasn't anything major," she says as prelude. "OK, don't laugh." Marques pledged to avoid chocolate for an entire month. Sounds pretty major to this chocophile.

She e-mailed a picture of herself having, shall we say, a bad hair day and no makeup. "I'm the least vain person I know, but trust me, we do have some vanities," she says. In other words, no way did she want that picture posted for all to see.

Lucky for Marques, she succeeded. "It's like having someone there to motivate you," she says. Picture or no picture, she wanted to meet her goal. She couldn't imagine telling her friends she failed at a no-chocolate diet.

Another user posted this goal: "All A+ this semester." (Still under way.) Yet another: "Speak to 10 CEOs." It failed. The picture shows a man next to a Ford Fiesta - not obviously embarrassing except perhaps to him.

"I guess different stuff embarrasses different people," Aherk!'s production director Jayme Cavalcanti wrote in an e-mail. "But we see a lot of people in weird costumes, and people making dumb faces. . . . Shame for posterity. There's an obvious humorous side to it, but it's surprisingly effective."

Among the successes?

"Pay rent without any late fees" and "DRUNK like a fish." (Obviously, not every user has lofty aims for self-improvement.)

Cavalcanti estimates that about 20 percent to 25 percent of goals are met. What happens to photos not posted? He says they are destroyed "but no 'proof' is provided to the user. It's pretty much our reputation on the line."

Marques says she has no idea what happened to her scary photo. "Maybe they'll use it to blackmail me," she jokes.

Cavalcanti has tried the site himself. He boasted that he could lose weight and sent in a picture of himself shirtless, beer belly exposed. He was busted. "It was most embarrassing," he says.

The site is well aware that sometimes Facebook friends are more like frenemies and just might skew the vote to get a look at the goods. But this isn't AA or even Weight Watchers. It's more playful.

Still, Erin Way, an assistant professor of psychology at Alvernia University, doesn't care for Aherk!'s big-stick approach to motivation.

"I would rather see a website that allows a person to define a goal and state a reward the person will give him or herself if the goal is met," she proposes. That's because going negative has its drawbacks - behavior changes are often short-lived and limited to a specific context.

Way points out that positive reinforcement is usually the preferred method, although punitive measures can work.

"Committing to anything in public, something that has been known for a long time in psychology, is a good way to get people to stick to their guns," says Andrew Ward, chair of the psychology department at Swarthmore College.

Social norms - in this case virtual humiliation - are powerful influencers on behavior, he says. Experiments have shown that an individual will go along with the larger group's answer to a question even if he or she knows it is not the correct response.

That's the case even if the group is made up of strangers.

"People," Ward says, "don't like to feel like a fool."