Feb. 16, 2012— -- Chad Zanca was devastated when his girlfriend of six months just vanished from sight while visiting him for a vacation in Costa Rica.

"She straight up gave me the cold shoulder. It was pretty brutal," said Zanca, a 25-year-old from Denver who works in strategic sales for Agility, a disaster-recovery service.

"When we came back to the States, we did our own thing for a few days," he said. "I called her and she didn't want to hang out with me. It was real cold, no explanation at all."

Zanca is happily playing the field today, but he'd still like to know what went wrong.

Singles like Zanca can now get the feedback on a free website, WotWentWrong, which was launched this year. They say it can give jilted lovers closure, and new insight into their dating missteps for future romances.

Site users can send a customized and secure feedback request to that date who never called back. The ex can reply by selecting various reasons for the silent treatment. There is room for either party to add additional text or questions.

To encourage a response, the site provides survey ratings on the long-lost ex or questions about attractiveness, kissing skills and dress. The emphasis is on "being nice," according to site developers.

Zanca said the idea is appealing and so did his co-worker, 25-year-old Lizzy Holmgren. "I would totally want to know why someone was not interested in me," she said.

The site will aggregate its statistics in March so users can see the top breakup reasons and other dating trivia.

"WotWentWrong is the breakup app for couples who never really broke up," founder Audrey Melnik of Melbourne, Australia, said. "Instead, someone just faded away, and the lack of explanation makes it difficult for the other party to move on. We're providing a socially acceptable way to tie up the loose ends, learn from what happened and improve your dating Zen for the next relationship, no stalking required."

Melnik, 35, and a former IT consultant from Melbourne based the site on her experience with bad breakups.

"A year ago, I went out with a guy; we had reconnected through Facebook," she said. "At first, I wasn't sure if I wanted a friendship or a hang-out thing. He was the pursuer. We went for drinks and it turned into dinner and then we went to his place and had a goodnight kiss. He walked me to my car and I never heard from him again."

She said now singles have an easy way to find out, rather than just kvetching with their friends. The site targets both men and women in the 18-to-45 age group.

Users can select from different templates and styles of communication -- "philosophical, sincere or cool" -- and customize them to individual needs. They get a feedback report when an ex responds.

About 25 percent of the requests have been answered so far, Melnik said. "We try to make it not to appear like a stalker or too clingy," she said.

So far, the site has drawn about 50,000 unique visitors and sent out 500 feedback requests. Half of its users live in the United States.

One, John Blalock of Auburn, Ala., stumbled across WotWentWrong while navigating the dating scene with a church singles group after his divorce. The 51-year-old IT specialist wasn't having much luck.

"It had been a long time since I had been in the dating world," he said.

Thinking it was a "novel concept," Blalock sent out requests to three former dates, all of whom had blown him off.

WotWentWrong Appeals to Dating Singles

"It gives you feedback from the point of self-esteem, something I struggle with at times," he said.

One of the women gave him affirmation about his good qualities, but then wrote a "negative," which Blalock said was helpful for future dates.

"It's really not attractive to tell a date what all the drink specials are at the local tavern," she wrote, according to Blalock.

"I thought I was being cute and witty," he said. "This lets you see the other person's perspective. It's very valuable."

But Caitlyn, a nursing student at New York University who asked that her last name not be used for fear of stalkers, was leery about learning her faults.

She, too, has had vanishing dates, mostly on Match.com.

"When you are single and trying to find somebody and everyone else has a boyfriend, you are uber-sensitive to a lot of things, and if someone tells me they didn't like me because I looked fat in an outfit, it would be an extra blow," the 27-year-old said.

But Caitlyn might be curious about the "little things," whether she chewed with her mouth open or talked too much on a date. "If it was something you could change, not your whole personality," she said.

Turn the tables, and Caitlyn said there are things that bothered her about her most recent date: He didn't pick up the tab for her drink. "Things like that turn me off," she said.

But would she respond if he had sent her a request for feedback through WotWentWrong?

"I'd like to tell him, but it would be awkward," she said. "I think I would, but in the nicest way possible."

Her friend, Briana Finney, 27, of Bucks County, Penn.,is also convinced love can't be measured by any online service and "cheapens" the art of dating.

"I think the writing is on the wall when a date did or didn't work out," Finney, a master's degree student, said.

"Chemistry is 80 percent of it and timing the other 20 percent. Having technology play another role in what used to be normal dating is ridiculous. You should feel it, if it was or wasn't there."

How can a woman be sure the former beau didn't "sugar coat" his response?

"The unknown is OK," Finney said. "I think that is really when you look in the mirror and decide to change or you just chalk it up to faith, that it wasn't meant to be."

But Corey Oliver, who works for a company that supplies games to physical education programs in Denver, said the key is whether the personal faults are "fixable."

"If it's just something that I can't do anything about, then no, I don't want to know, because it would make me self-conscious or pissed," the 25-year-old said. "But if it's something serious, more power to them. I'd rather hear it earlier than later."